pep8 reformatted

68 files changed, 1029 insertions, 541 deletions

diff --git a/pysnmp/carrier/asyncio/base.py b/pysnmp/carrier/asyncio/base.py
index 002239bb..217092a6 100644
--- a/pysnmp/carrier/asyncio/base.py
+++ b/pysnmp/carrier/asyncio/base.py
@@ -33,6 +33,7 @@
 from pysnmp.carrier.asyncio.dispatch import AsyncioDispatcher
 from pysnmp.carrier.base import AbstractTransport
 
+
 class AbstractAsyncioTransport(AbstractTransport):
     protoTransportDispatcher = AsyncioDispatcher
     """Base Asyncio Transport, to be used with AsyncioDispatcher"""
diff --git a/pysnmp/carrier/asyncio/dgram/base.py b/pysnmp/carrier/asyncio/dgram/base.py
index 5c3b78b6..3abcc3a3 100644
--- a/pysnmp/carrier/asyncio/dgram/base.py
+++ b/pysnmp/carrier/asyncio/dgram/base.py
@@ -35,6 +35,7 @@ import traceback
 from pysnmp.carrier.asyncio.base import AbstractAsyncioTransport
 from pysnmp.carrier import error
 from pysnmp import debug
+
 try:
     import asyncio
 except ImportError:
@@ -42,14 +43,16 @@ except ImportError:
 
 loop = asyncio.get_event_loop()
 
+
 class DgramAsyncioProtocol(asyncio.DatagramProtocol, AbstractAsyncioTransport):
     """Base Asyncio datagram Transport, to be used with AsyncioDispatcher"""
     sockFamily = None
     addressType = lambda x: x
     transport = None
 
-    def __init__(self, *args, **kwargs):
+    def __init__(self, sock=None, sockMap=None):
         self._writeQ = []
+        self._lport = None
 
     def datagram_received(self, datagram, transportAddress):
         if self._cbFun is None:
@@ -95,7 +98,8 @@ class DgramAsyncioProtocol(asyncio.DatagramProtocol, AbstractAsyncioTransport):
         return self
 
     def closeTransport(self):
-        self._lport.cancel()
+        if self._lport is not None:
+            self._lport.cancel()
         if self.transport is not None:
             self.transport.close()
         AbstractAsyncioTransport.closeTransport(self)
diff --git a/pysnmp/carrier/asyncio/dgram/udp.py b/pysnmp/carrier/asyncio/dgram/udp.py
index aa73fb10..f80de36b 100644
--- a/pysnmp/carrier/asyncio/dgram/udp.py
+++ b/pysnmp/carrier/asyncio/dgram/udp.py
@@ -33,6 +33,7 @@
 import socket
 from pysnmp.carrier.base import AbstractTransportAddress
 from pysnmp.carrier.asyncio.dgram.base import DgramAsyncioProtocol
+
 try:
     import asyncio
 except ImportError:
@@ -42,11 +43,14 @@ loop = asyncio.get_event_loop()
 
 domainName = snmpUDPDomain = (1, 3, 6, 1, 6, 1, 1)
 
+
 class UdpTransportAddress(tuple, AbstractTransportAddress):
     pass
 
+
 class UdpAsyncioTransport(DgramAsyncioProtocol):
     sockFamily = socket.AF_INET
     addressType = UdpTransportAddress
 
+
 UdpTransport = UdpAsyncioTransport
diff --git a/pysnmp/carrier/asyncio/dgram/udp6.py b/pysnmp/carrier/asyncio/dgram/udp6.py
index ad3c28dd..290c03bd 100644
--- a/pysnmp/carrier/asyncio/dgram/udp6.py
+++ b/pysnmp/carrier/asyncio/dgram/udp6.py
@@ -7,6 +7,7 @@
 import socket
 from pysnmp.carrier.base import AbstractTransportAddress
 from pysnmp.carrier.asyncio.dgram.base import DgramAsyncioProtocol
+
 try:
     import asyncio
 except ImportError:
@@ -16,9 +17,11 @@ loop = asyncio.get_event_loop()
 
 domainName = snmpUDP6Domain = (1, 3, 6, 1, 2, 1, 100, 1, 2)
 
+
 class Udp6TransportAddress(tuple, AbstractTransportAddress):
     pass
 
+
 class Udp6AsyncioTransport(DgramAsyncioProtocol):
     sockFamily = socket.has_ipv6 and socket.AF_INET6 or None
     addressType = Udp6TransportAddress
@@ -28,9 +31,10 @@ class Udp6AsyncioTransport(DgramAsyncioProtocol):
             return self.addressType((transportAddress[0].split('%')[0],
                                      transportAddress[1],
                                      0,  # flowinfo
-                                     0)) # scopeid
+                                     0))  # scopeid
         else:
             return self.addressType((transportAddress[0],
                                      transportAddress[1], 0, 0))
 
+
 Udp6Transport = Udp6AsyncioTransport
diff --git a/pysnmp/carrier/asyncio/dispatch.py b/pysnmp/carrier/asyncio/dispatch.py
index 0cfa4ceb..cb4c0941 100644
--- a/pysnmp/carrier/asyncio/dispatch.py
+++ b/pysnmp/carrier/asyncio/dispatch.py
@@ -34,6 +34,7 @@ import sys
 import traceback
 from pysnmp.carrier.base import AbstractTransportDispatcher
 from pysnmp.error import PySnmpError
+
 try:
     import asyncio
 except ImportError:
@@ -41,8 +42,10 @@ except ImportError:
 
 loop = asyncio.get_event_loop()
 
+
 class AsyncioDispatcher(AbstractTransportDispatcher):
     """AsyncioDispatcher based on asyncio event loop"""
+
     def __init__(self, *args, **kwargs):
         AbstractTransportDispatcher.__init__(self)
         self.__transportCount = 0
@@ -70,7 +73,7 @@ class AsyncioDispatcher(AbstractTransportDispatcher):
             self.loopingcall = asyncio.async(self.handle_timeout())
         AbstractTransportDispatcher.registerTransport(
             self, tDomain, transport
-            )
+        )
         self.__transportCount += 1
 
     def unregisterTransport(self, tDomain):
@@ -84,9 +87,10 @@ class AsyncioDispatcher(AbstractTransportDispatcher):
             self.loopingcall.cancel()
             self.loopingcall = None
 
+
 # Trollius or Tulip?
 if not hasattr(asyncio, "From"):
-    exec("""\
+    exec ("""\
 @asyncio.coroutine
 def handle_timeout(self):
     while True:
@@ -94,4 +98,3 @@ def handle_timeout(self):
         self.handleTimerTick(loop.time())
 AsyncioDispatcher.handle_timeout = handle_timeout\
 """)
-
diff --git a/pysnmp/carrier/asyncore/base.py b/pysnmp/carrier/asyncore/base.py
index da68774d..04044775 100644
--- a/pysnmp/carrier/asyncore/base.py
+++ b/pysnmp/carrier/asyncore/base.py
@@ -4,13 +4,15 @@
 # Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
 # License: http://pysnmp.sf.net/license.html
 #
-import socket, sys
+import socket
+import sys
 import asyncore
 from pysnmp.carrier import error
 from pysnmp.carrier.base import AbstractTransport
 from pysnmp.carrier.asyncore.dispatch import AsyncoreDispatcher
 from pysnmp import debug
 
+
 class AbstractSocketTransport(asyncore.dispatcher, AbstractTransport):
     protoTransportDispatcher = AsyncoreDispatcher
     sockFamily = sockType = None
@@ -25,11 +27,11 @@ class AbstractSocketTransport(asyncore.dispatcher, AbstractTransport):
             if self.sockFamily is None:
                 raise error.CarrierError(
                     'Address family %s not supported' % self.__class__.__name__
-                    )
+                )
             if self.sockType is None:
                 raise error.CarrierError(
                     'Socket type %s not supported' % self.__class__.__name__
-                    )
+                )
             try:
                 sock = socket.socket(self.sockFamily, self.sockType)
             except socket.error:
@@ -42,7 +44,7 @@ class AbstractSocketTransport(asyncore.dispatcher, AbstractTransport):
                         sock.setsockopt(socket.SOL_SOCKET, b, self.bufferSize)
                         debug.logger & debug.flagIO and debug.logger('%s: socket %d buffer size increased from %d to %d for buffer %d' % (self.__class__.__name__, sock.fileno(), bsize, self.bufferSize, b))
             except Exception:
-                debug.logger & debug.flagIO and debug.logger('%s: socket buffer size option mangling failure for buffer %d: %s' % (self.__class__.__name__, b, sys.exc_info()[1]))
+                debug.logger & debug.flagIO and debug.logger('%s: socket buffer size option mangling failure for buffer: %s' % (self.__class__.__name__, sys.exc_info()[1]))
 
         # The socket map is managed by the AsyncoreDispatcher on
         # which this transport is registered. Here we just prepare
diff --git a/pysnmp/carrier/asyncore/dgram/base.py b/pysnmp/carrier/asyncore/dgram/base.py
index c64b7e89..49b7846e 100644
--- a/pysnmp/carrier/asyncore/dgram/base.py
+++ b/pysnmp/carrier/asyncore/dgram/base.py
@@ -4,7 +4,9 @@
 # Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
 # License: http://pysnmp.sf.net/license.html
 #
-import socket, errno, sys
+import socket
+import errno
+import sys
 from pysnmp.carrier.asyncore.base import AbstractSocketTransport
 from pysnmp.carrier import sockfix, sockmsg, error
 from pysnmp import debug
@@ -21,17 +23,21 @@ if hasattr(errno, 'EBADFD'):
     # bad FD may happen upon FD closure on n-1 select() event
     sockErrors[errno.EBADFD] = True
 
+
 class DgramSocketTransport(AbstractSocketTransport):
     sockType = socket.SOCK_DGRAM
     retryCount = 3
     retryInterval = 1
     addressType = lambda x: x
+
     def __init__(self, sock=None, sockMap=None):
         self.__outQueue = []
         self._sendto = lambda s, b, a: s.sendto(b, a)
+
         def __recvfrom(s, sz):
             d, a = s.recvfrom(sz)
             return d, self.addressType(a)
+
         self._recvfrom = __recvfrom
         AbstractSocketTransport.__init__(self, sock, sockMap)
 
@@ -40,10 +46,11 @@ class DgramSocketTransport(AbstractSocketTransport):
             try:
                 self.socket.bind(iface)
             except socket.error:
-                raise error.CarrierError('bind() for %s failed: %s' % (iface is None and "<all local>" or iface, sys.exc_info()[1]))
+                raise error.CarrierError(
+                    'bind() for %s failed: %s' % (iface is None and "<all local>" or iface, sys.exc_info()[1]))
         return self
 
-    def openServerMode(self, iface=None):
+    def openServerMode(self, iface):
         try:
             self.socket.bind(iface)
         except socket.error:
@@ -62,7 +69,7 @@ class DgramSocketTransport(AbstractSocketTransport):
 
     def enablePktInfo(self, flag=1):
         if not hasattr(self.socket, 'sendmsg') or \
-           not hasattr(self.socket, 'recvmsg'):
+                not hasattr(self.socket, 'recvmsg'):
             raise error.CarrierError('sendmsg()/recvmsg() interface is not supported by this OS and/or Python version')
 
         try:
@@ -100,7 +107,7 @@ class DgramSocketTransport(AbstractSocketTransport):
     def sendMessage(self, outgoingMessage, transportAddress):
         self.__outQueue.append(
             (outgoingMessage, self.normalizeAddress(transportAddress))
-            )
+        )
         debug.logger & debug.flagIO and debug.logger('sendMessage: outgoingMessage queued (%d octets) %s' % (len(outgoingMessage), debug.hexdump(outgoingMessage)))
 
     def normalizeAddress(self, transportAddress):
@@ -114,8 +121,8 @@ class DgramSocketTransport(AbstractSocketTransport):
         # one evil OS does not seem to support getsockname() for DGRAM sockets
         try:
             return self.socket.getsockname()
-        except:
-            return ('0.0.0.0', 0)
+        except Exception:
+            return '0.0.0.0', 0
 
     # asyncore API
     def handle_connect(self):
@@ -145,11 +152,10 @@ class DgramSocketTransport(AbstractSocketTransport):
 
     def handle_read(self):
         try:
-            incomingMessage, transportAddress = self._recvfrom(
-                self.socket, 65535
-            )
+            incomingMessage, transportAddress = self._recvfrom(self.socket, 65535)
             transportAddress = self.normalizeAddress(transportAddress)
-            debug.logger & debug.flagIO and debug.logger('handle_read: transportAddress %r -> %r incomingMessage (%d octets) %s' % (transportAddress, transportAddress.getLocalAddress(), len(incomingMessage), debug.hexdump(incomingMessage)))
+            debug.logger & debug.flagIO and debug.logger(
+                'handle_read: transportAddress %r -> %r incomingMessage (%d octets) %s' % (transportAddress, transportAddress.getLocalAddress(), len(incomingMessage), debug.hexdump(incomingMessage)))
             if not incomingMessage:
                 self.handle_close()
                 return
@@ -165,4 +171,4 @@ class DgramSocketTransport(AbstractSocketTransport):
                 raise error.CarrierError('recvfrom() failed: %s' % (sys.exc_info()[1],))
 
     def handle_close(self):
-        pass # no datagram connection
+        pass  # no datagram connection
diff --git a/pysnmp/carrier/asyncore/dgram/udp.py b/pysnmp/carrier/asyncore/dgram/udp.py
index f8b5ac1b..09b783dd 100644
--- a/pysnmp/carrier/asyncore/dgram/udp.py
+++ b/pysnmp/carrier/asyncore/dgram/udp.py
@@ -10,11 +10,14 @@ from pysnmp.carrier.asyncore.dgram.base import DgramSocketTransport
 
 domainName = snmpUDPDomain = (1, 3, 6, 1, 6, 1, 1)
 
+
 class UdpTransportAddress(tuple, AbstractTransportAddress):
     pass
 
+
 class UdpSocketTransport(DgramSocketTransport):
     sockFamily = AF_INET
     addressType = UdpTransportAddress
 
+
 UdpTransport = UdpSocketTransport
diff --git a/pysnmp/carrier/asyncore/dgram/udp6.py b/pysnmp/carrier/asyncore/dgram/udp6.py
index 947ecd23..c659dc35 100644
--- a/pysnmp/carrier/asyncore/dgram/udp6.py
+++ b/pysnmp/carrier/asyncore/dgram/udp6.py
@@ -11,9 +11,11 @@ import socket
 
 domainName = snmpUDP6Domain = (1, 3, 6, 1, 2, 1, 100, 1, 2)
 
+
 class Udp6TransportAddress(tuple, AbstractTransportAddress):
     pass
 
+
 class Udp6SocketTransport(DgramSocketTransport):
     sockFamily = socket.has_ipv6 and socket.AF_INET6 or None
     addressType = Udp6TransportAddress
@@ -22,7 +24,7 @@ class Udp6SocketTransport(DgramSocketTransport):
         if '%' in transportAddress[0]:  # strip zone ID
             ta = self.addressType((transportAddress[0].split('%')[0],
                                    transportAddress[1],
-                                   0,   # flowinfo
+                                   0,  # flowinfo
                                    0))  # scopeid
         else:
             ta = self.addressType((transportAddress[0],
@@ -34,4 +36,5 @@ class Udp6SocketTransport(DgramSocketTransport):
         else:
             return ta.setLocalAddress(self.getLocalAddress())
 
+
 Udp6Transport = Udp6SocketTransport
diff --git a/pysnmp/carrier/asyncore/dgram/unix.py b/pysnmp/carrier/asyncore/dgram/unix.py
index f8b193eb..7bac79af 100644
--- a/pysnmp/carrier/asyncore/dgram/unix.py
+++ b/pysnmp/carrier/asyncore/dgram/unix.py
@@ -6,6 +6,7 @@
 #
 import os
 import random
+
 try:
     from socket import AF_UNIX
 except ImportError:
@@ -17,12 +18,15 @@ domainName = snmpLocalDomain = (1, 3, 6, 1, 2, 1, 100, 1, 13)
 
 random.seed()
 
+
 class UnixTransportAddress(str, AbstractTransportAddress):
     pass
 
+
 class UnixSocketTransport(DgramSocketTransport):
     sockFamily = AF_UNIX
     addressType = UnixTransportAddress
+    _iface = ''
 
     def openClientMode(self, iface=None):
         if iface is None:
@@ -35,21 +39,22 @@ class UnixSocketTransport(DgramSocketTransport):
         if os.path.exists(iface):
             os.remove(iface)
         DgramSocketTransport.openClientMode(self, iface)
-        self.__iface = iface
+        self._iface = iface
         return self
 
     def openServerMode(self, iface):
         DgramSocketTransport.openServerMode(self, iface)
-        self.__iface = iface
+        self._iface = iface
         return self
 
     def closeTransport(self):
         DgramSocketTransport.closeTransport(self)
         try:
-            os.remove(self.__iface)
+            os.remove(self._iface)
         except OSError:
             pass
 
+
 UnixTransport = UnixSocketTransport
 
 # Compatibility stub
diff --git a/pysnmp/carrier/asyncore/dispatch.py b/pysnmp/carrier/asyncore/dispatch.py
index ae602549..78f6dcf8 100644
--- a/pysnmp/carrier/asyncore/dispatch.py
+++ b/pysnmp/carrier/asyncore/dispatch.py
@@ -12,9 +12,10 @@ from asyncore import loop
 from pysnmp.carrier.base import AbstractTransportDispatcher
 from pysnmp.error import PySnmpError
 
+
 class AsyncoreDispatcher(AbstractTransportDispatcher):
     def __init__(self):
-        self.__sockMap = {} # use own map for MT safety
+        self.__sockMap = {}  # use own map for MT safety
         self.timeout = 0.5
         AbstractTransportDispatcher.__init__(self)
 
diff --git a/pysnmp/carrier/base.py b/pysnmp/carrier/base.py
index 3aa2de4e..653ea3fe 100644
--- a/pysnmp/carrier/base.py
+++ b/pysnmp/carrier/base.py
@@ -6,6 +6,7 @@
 #
 from pysnmp.carrier import error
 
+
 class TimerCallable:
     def __init__(self, cbFun, callInterval):
         self.__cbFun = cbFun
@@ -35,6 +36,7 @@ class TimerCallable:
     def __ge__(self, cbFun):
         return self.__cbFun >= cbFun
 
+
 class AbstractTransportDispatcher:
     def __init__(self):
         self.__transports = {}
@@ -54,7 +56,7 @@ class AbstractTransportDispatcher:
         else:
             raise error.CarrierError(
                 'Unregistered transport %s' % (incomingTransport,)
-                )
+            )
 
         if self.__routingCbFun:
             recvId = self.__routingCbFun(
@@ -69,7 +71,7 @@ class AbstractTransportDispatcher:
             )
         else:
             raise error.CarrierError(
-                'No callback for "%r" found - loosing incoming event'%(recvId,)
+                'No callback for "%r" found - loosing incoming event' % (recvId,)
             )
 
     # Dispatcher API
@@ -111,7 +113,7 @@ class AbstractTransportDispatcher:
         if tDomain in self.__transports:
             raise error.CarrierError(
                 'Transport %s already registered' % (tDomain,)
-                )
+            )
         transport.registerCbFun(self._cbFun)
         self.__transports[tDomain] = transport
         self.__transportDomainMap[transport] = tDomain
@@ -120,7 +122,7 @@ class AbstractTransportDispatcher:
         if tDomain not in self.__transports:
             raise error.CarrierError(
                 'Transport %s not registered' % (tDomain,)
-                )
+            )
         self.__transports[tDomain].unregisterCbFun()
         del self.__transportDomainMap[self.__transports[tDomain]]
         del self.__transports[tDomain]
@@ -130,18 +132,18 @@ class AbstractTransportDispatcher:
             return self.__transports[transportDomain]
         raise error.CarrierError(
             'Transport %s not registered' % (transportDomain,)
-            )
+        )
 
     def sendMessage(self, outgoingMessage, transportDomain,
                     transportAddress):
         if transportDomain in self.__transports:
             self.__transports[transportDomain].sendMessage(
                 outgoingMessage, transportAddress
-                )
+            )
         else:
             raise error.CarrierError(
                 'No suitable transport domain for %s' % (transportDomain,)
-                )
+            )
 
     def getTimerResolution(self):
         return self.__timerResolution
@@ -156,7 +158,7 @@ class AbstractTransportDispatcher:
         return self.__ticks
 
     def handleTimerTick(self, timeNow):
-        if self.__nextTime == 0:   # initial initialization
+        if self.__nextTime == 0:  # initial initialization
             self.__nextTime = timeNow + self.__timerResolution - self.__timerDelta
 
         if self.__nextTime >= timeNow:
@@ -180,10 +182,7 @@ class AbstractTransportDispatcher:
             del self.__jobs[jobId]
 
     def jobsArePending(self):
-        if self.__jobs:
-            return 1
-        else:
-            return 0
+        return bool(self.__jobs)
 
     def runDispatcher(self, timeout=0.0):
         raise error.CarrierError('Method not implemented')
@@ -196,8 +195,10 @@ class AbstractTransportDispatcher:
         self.unregisterRecvCbFun()
         self.unregisterTimerCbFun()
 
+
 class AbstractTransportAddress:
     _localAddress = None
+
     def setLocalAddress(self, s):
         self._localAddress = s
         return self
@@ -208,10 +209,12 @@ class AbstractTransportAddress:
     def clone(self, localAddress=None):
         return self.__class__(self).setLocalAddress(localAddress is None and self.getLocalAddress() or localAddress)
 
+
 class AbstractTransport:
     protoTransportDispatcher = None
     addressType = AbstractTransportAddress
     _cbFun = None
+
     @classmethod
     def isCompatibleWithDispatcher(cls, transportDispatcher):
         return isinstance(transportDispatcher, cls.protoTransportDispatcher)
@@ -220,7 +223,7 @@ class AbstractTransport:
         if self._cbFun:
             raise error.CarrierError(
                 'Callback function %s already registered at %s' % (self._cbFun, self)
-                )
+            )
         self._cbFun = cbFun
 
     def unregisterCbFun(self):
@@ -234,7 +237,7 @@ class AbstractTransport:
     def openClientMode(self, iface=None):
         raise error.CarrierError('Method not implemented')
 
-    def openServerMode(self, iface=None):
+    def openServerMode(self, iface):
         raise error.CarrierError('Method not implemented')
 
     def sendMessage(self, outgoingMessage, transportAddress):
diff --git a/pysnmp/carrier/error.py b/pysnmp/carrier/error.py
index cdc3b308..290eb659 100644
--- a/pysnmp/carrier/error.py
+++ b/pysnmp/carrier/error.py
@@ -6,5 +6,6 @@
 #
 from pysnmp import error
 
+
 class CarrierError(error.PySnmpError):
     pass
diff --git a/pysnmp/carrier/sockfix.py b/pysnmp/carrier/sockfix.py
index 3abcd932..4c84321a 100644
--- a/pysnmp/carrier/sockfix.py
+++ b/pysnmp/carrier/sockfix.py
@@ -7,11 +7,11 @@
 import socket
 
 symbols = {
-    'IP_PKTINFO':       8,
-    'IP_TRANSPARENT':   19,
-    'SOL_IPV6':         41,
+    'IP_PKTINFO': 8,
+    'IP_TRANSPARENT': 19,
+    'SOL_IPV6': 41,
     'IPV6_RECVPKTINFO': 49,
-    'IPV6_PKTINFO':     50
+    'IPV6_PKTINFO': 50
 }
 
 for symbol in symbols:
diff --git a/pysnmp/carrier/twisted/base.py b/pysnmp/carrier/twisted/base.py
index 60f300ef..590717df 100644
--- a/pysnmp/carrier/twisted/base.py
+++ b/pysnmp/carrier/twisted/base.py
@@ -15,7 +15,10 @@
 from pysnmp.carrier.twisted.dispatch import TwistedDispatcher
 from pysnmp.carrier.base import AbstractTransport
 
+
 class AbstractTwistedTransport(AbstractTransport):
     protoTransportDispatcher = TwistedDispatcher
-    def __init__(self):
+
+    def __init__(self, sock=None, sockMap=None):
         self._writeQ = []
+        DgramTwistedTransport.__init__(self)
diff --git a/pysnmp/carrier/twisted/dgram/base.py b/pysnmp/carrier/twisted/dgram/base.py
index 4c556a4a..9dd2334b 100644
--- a/pysnmp/carrier/twisted/dgram/base.py
+++ b/pysnmp/carrier/twisted/dgram/base.py
@@ -11,6 +11,7 @@ from pysnmp.carrier.twisted.base import AbstractTwistedTransport
 from pysnmp.carrier import error
 from pysnmp import debug
 
+
 class DgramTwistedTransport(DatagramProtocol, AbstractTwistedTransport):
     """Base Twisted datagram Transport, to be used with TwistedDispatcher"""
 
diff --git a/pysnmp/carrier/twisted/dgram/udp.py b/pysnmp/carrier/twisted/dgram/udp.py
index 658359f6..3bf06413 100644
--- a/pysnmp/carrier/twisted/dgram/udp.py
+++ b/pysnmp/carrier/twisted/dgram/udp.py
@@ -12,11 +12,14 @@ from pysnmp.carrier import error
 
 domainName = snmpUDPDomain = (1, 3, 6, 1, 6, 1, 1)
 
+
 class UdpTransportAddress(tuple, AbstractTransportAddress):
     pass
 
+
 class UdpTwistedTransport(DgramTwistedTransport):
     addressType = UdpTransportAddress
+    _lport = None
 
     # AbstractTwistedTransport API
 
@@ -37,8 +40,11 @@ class UdpTwistedTransport(DgramTwistedTransport):
         return self
 
     def closeTransport(self):
-        d = self._lport.stopListening()
-        d and d.addCallback(lambda x: None)
-        DgramTwistedTransport.closeTransport(self)
+        if self._lport is not None:
+            d = self._lport.stopListening()
+            if d:
+                d.addCallback(lambda x: None)
+            DgramTwistedTransport.closeTransport(self)
+
 
 UdpTransport = UdpTwistedTransport
diff --git a/pysnmp/carrier/twisted/dgram/unix.py b/pysnmp/carrier/twisted/dgram/unix.py
index 5dc84bd3..61ccff93 100644
--- a/pysnmp/carrier/twisted/dgram/unix.py
+++ b/pysnmp/carrier/twisted/dgram/unix.py
@@ -17,6 +17,7 @@ class UnixTransportAddress(str, AbstractTransportAddress):
 
 class UnixTwistedTransport(DgramTwistedTransport):
     addressType = UnixTransportAddress
+    _lport = None
 
     # AbstractTwistedTransport API
 
@@ -27,7 +28,7 @@ class UnixTwistedTransport(DgramTwistedTransport):
             raise error.CarrierError(sys.exc_info()[1])
         return self
 
-    def openServerMode(self, iface=None):
+    def openServerMode(self, iface):
         try:
             self._lport = reactor.listenUNIXDatagram(iface, self)
         except Exception:
@@ -36,8 +37,10 @@ class UnixTwistedTransport(DgramTwistedTransport):
         return self
 
     def closeTransport(self):
-        d = self._lport.stopListening()
-        d and d.addCallback(lambda x: None)
+        if self._lport is not None:
+            d = self._lport.stopListening()
+            if d:
+                d.addCallback(lambda x: None)
         DgramTwistedTransport.closeTransport(self)
 
 UnixTransport = UnixTwistedTransport
diff --git a/pysnmp/carrier/twisted/dispatch.py b/pysnmp/carrier/twisted/dispatch.py
index 4cadec32..04cf9fae 100644
--- a/pysnmp/carrier/twisted/dispatch.py
+++ b/pysnmp/carrier/twisted/dispatch.py
@@ -17,8 +17,10 @@ from twisted.internet import reactor, task
 from pysnmp.carrier.base import AbstractTransportDispatcher
 from pysnmp.error import PySnmpError
 
+
 class TwistedDispatcher(AbstractTransportDispatcher):
     """TransportDispatcher based on twisted.internet.reactor"""
+
     def __init__(self, *args, **kwargs):
         AbstractTransportDispatcher.__init__(self)
         self.__transportCount = 0
diff --git a/pysnmp/entity/config.py b/pysnmp/entity/config.py
index f66b0b54..10acd25b 100644
--- a/pysnmp/entity/config.py
+++ b/pysnmp/entity/config.py
@@ -46,13 +46,16 @@ privServices = {des.Des.serviceID: des.Des(),
                 aes256.Aes256.serviceID: aes256.Aes256(),
                 nopriv.NoPriv.serviceID: nopriv.NoPriv()}
 
+
 def __cookV1SystemInfo(snmpEngine, communityIndex):
-    snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
 
-    snmpCommunityEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-COMMUNITY-MIB', 'snmpCommunityEntry')
+    snmpEngineID, = mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+    snmpCommunityEntry, = mibBuilder.importSymbols('SNMP-COMMUNITY-MIB', 'snmpCommunityEntry')
     tblIdx = snmpCommunityEntry.getInstIdFromIndices(communityIndex)
     return snmpCommunityEntry, tblIdx, snmpEngineID
 
+
 def addV1System(snmpEngine, communityIndex, communityName,
                 contextEngineId=None, contextName=None,
                 transportTag=None, securityName=None):
@@ -81,6 +84,7 @@ def addV1System(snmpEngine, communityIndex, communityName,
          (snmpCommunityEntry.name + (8,) + tblIdx, 'createAndGo'))
     )
 
+
 def delV1System(snmpEngine, communityIndex):
     (snmpCommunityEntry, tblIdx,
      snmpEngineID) = __cookV1SystemInfo(snmpEngine, communityIndex)
@@ -88,21 +92,26 @@ def delV1System(snmpEngine, communityIndex):
         ((snmpCommunityEntry.name + (8,) + tblIdx, 'destroy'),)
     )
 
+
 def __cookV3UserInfo(snmpEngine, securityName, securityEngineId):
-    snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+    snmpEngineID, = mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+
     if securityEngineId is None:
         snmpEngineID = snmpEngineID.syntax
     else:
         snmpEngineID = snmpEngineID.syntax.clone(securityEngineId)
 
-    usmUserEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-USER-BASED-SM-MIB', 'usmUserEntry')
+    usmUserEntry, = mibBuilder.importSymbols('SNMP-USER-BASED-SM-MIB', 'usmUserEntry')
     tblIdx1 = usmUserEntry.getInstIdFromIndices(snmpEngineID, securityName)
 
-    pysnmpUsmSecretEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('PYSNMP-USM-MIB', 'pysnmpUsmSecretEntry')
+    pysnmpUsmSecretEntry, = mibBuilder.importSymbols('PYSNMP-USM-MIB', 'pysnmpUsmSecretEntry')
     tblIdx2 = pysnmpUsmSecretEntry.getInstIdFromIndices(securityName)
 
     return snmpEngineID, usmUserEntry, tblIdx1, pysnmpUsmSecretEntry, tblIdx2
 
+
 def addV3User(snmpEngine, userName,
               authProtocol=usmNoAuthProtocol, authKey=None,
               privProtocol=usmNoPrivProtocol, privKey=None,
@@ -110,18 +119,20 @@ def addV3User(snmpEngine, userName,
               securityName=None,
               # deprecated parameters follow
               contextEngineId=None):
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
     if securityName is None:
         securityName = userName
     if securityEngineId is None:  # backward compatibility
         securityEngineId = contextEngineId
-    (snmpEngineID, usmUserEntry, tblIdx1, pysnmpUsmSecretEntry,
-     tblIdx2) = __cookV3UserInfo(snmpEngine, userName, securityEngineId)
+    (snmpEngineID, usmUserEntry, tblIdx1,
+     pysnmpUsmSecretEntry, tblIdx2) = __cookV3UserInfo(snmpEngine, userName, securityEngineId)
 
     # Load augmenting table before creating new row in base one
-    pysnmpUsmKeyEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('PYSNMP-USM-MIB', 'pysnmpUsmKeyEntry')
+    pysnmpUsmKeyEntry, = mibBuilder.importSymbols('PYSNMP-USM-MIB', 'pysnmpUsmKeyEntry')
 
     # Load clone-from (may not be needed)
-    zeroDotZero, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMPv2-SMI', 'zeroDotZero')
+    zeroDotZero, = mibBuilder.importSymbols('SNMPv2-SMI', 'zeroDotZero')
 
     snmpEngine.msgAndPduDsp.mibInstrumController.writeVars(
         ((usmUserEntry.name + (13,) + tblIdx1, 'destroy'),)
@@ -176,6 +187,7 @@ def addV3User(snmpEngine, userName,
          (pysnmpUsmSecretEntry.name + (4,) + tblIdx2, 'createAndGo'))
     )
 
+
 def delV3User(snmpEngine,
               userName,
               securityEngineId=None,
@@ -196,7 +208,7 @@ def delV3User(snmpEngine,
     varBinds = initialVarBinds = (
         (usmUserEntry.name + (1,), None),  # usmUserEngineID
         (usmUserEntry.name + (2,), None),  # usmUserName
-        (usmUserEntry.name + (4,), None)   # usmUserCloneFrom
+        (usmUserEntry.name + (4,), None)  # usmUserCloneFrom
     )
     while varBinds:
         varBinds = snmpEngine.msgAndPduDsp.mibInstrumController.readNextVars(
@@ -210,11 +222,15 @@ def delV3User(snmpEngine,
             delV3User(snmpEngine, varBinds[1][1], varBinds[0][1])
             varBinds = initialVarBinds
 
+
 def __cookTargetParamsInfo(snmpEngine, name):
-    snmpTargetParamsEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-TARGET-MIB', 'snmpTargetParamsEntry')
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+    snmpTargetParamsEntry, = mibBuilder.importSymbols('SNMP-TARGET-MIB', 'snmpTargetParamsEntry')
     tblIdx = snmpTargetParamsEntry.getInstIdFromIndices(name)
     return snmpTargetParamsEntry, tblIdx
 
+
 # mpModel: 0 == SNMPv1, 1 == SNMPv2c, 3 == SNMPv3
 def addTargetParams(snmpEngine, name, securityName, securityLevel, mpModel=3):
     if mpModel == 0:
@@ -240,32 +256,39 @@ def addTargetParams(snmpEngine, name, securityName, securityLevel, mpModel=3):
          (snmpTargetParamsEntry.name + (7,) + tblIdx, 'createAndGo'))
     )
 
+
 def delTargetParams(snmpEngine, name):
     snmpTargetParamsEntry, tblIdx = __cookTargetParamsInfo(snmpEngine, name)
     snmpEngine.msgAndPduDsp.mibInstrumController.writeVars(
         ((snmpTargetParamsEntry.name + (7,) + tblIdx, 'destroy'),)
     )
 
+
 def __cookTargetAddrInfo(snmpEngine, addrName):
-    snmpTargetAddrEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-TARGET-MIB', 'snmpTargetAddrEntry')
-    snmpSourceAddrEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('PYSNMP-SOURCE-MIB', 'snmpSourceAddrEntry')
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+    snmpTargetAddrEntry, = mibBuilder.importSymbols('SNMP-TARGET-MIB', 'snmpTargetAddrEntry')
+    snmpSourceAddrEntry, = mibBuilder.importSymbols('PYSNMP-SOURCE-MIB', 'snmpSourceAddrEntry')
     tblIdx = snmpTargetAddrEntry.getInstIdFromIndices(addrName)
     return snmpTargetAddrEntry, snmpSourceAddrEntry, tblIdx
 
+
 def addTargetAddr(snmpEngine, addrName, transportDomain, transportAddress,
                   params, timeout=None, retryCount=None, tagList=null,
                   sourceAddress=None):
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
     (snmpTargetAddrEntry, snmpSourceAddrEntry,
      tblIdx) = __cookTargetAddrInfo(snmpEngine, addrName)
 
     if transportDomain[:len(snmpUDPDomain)] == snmpUDPDomain:
-        SnmpUDPAddress, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMPv2-TM', 'SnmpUDPAddress')
+        SnmpUDPAddress, = mibBuilder.importSymbols('SNMPv2-TM', 'SnmpUDPAddress')
         transportAddress = SnmpUDPAddress(transportAddress)
         if sourceAddress is None:
             sourceAddress = ('0.0.0.0', 0)
         sourceAddress = SnmpUDPAddress(sourceAddress)
     elif transportDomain[:len(snmpUDP6Domain)] == snmpUDP6Domain:
-        TransportAddressIPv6, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('TRANSPORT-ADDRESS-MIB', 'TransportAddressIPv6')
+        TransportAddressIPv6, = mibBuilder.importSymbols('TRANSPORT-ADDRESS-MIB', 'TransportAddressIPv6')
         transportAddress = TransportAddressIPv6(transportAddress)
         if sourceAddress is None:
             sourceAddress = ('::', 0)
@@ -286,6 +309,7 @@ def addTargetAddr(snmpEngine, addrName, transportDomain, transportAddress,
          (snmpTargetAddrEntry.name + (9,) + tblIdx, 'createAndGo'))
     )
 
+
 def delTargetAddr(snmpEngine, addrName):
     (snmpTargetAddrEntry, snmpSourceAddrEntry,
      tblIdx) = __cookTargetAddrInfo(snmpEngine, addrName)
@@ -293,10 +317,12 @@ def delTargetAddr(snmpEngine, addrName):
         ((snmpTargetAddrEntry.name + (9,) + tblIdx, 'destroy'),)
     )
 
+
 def addTransport(snmpEngine, transportDomain, transport):
     if snmpEngine.transportDispatcher:
         if not transport.isCompatibleWithDispatcher(snmpEngine.transportDispatcher):
-            raise error.PySnmpError('Transport %r is not compatible with dispatcher %r' % (transport, snmpEngine.transportDispatcher))
+            raise error.PySnmpError(
+                'Transport %r is not compatible with dispatcher %r' % (transport, snmpEngine.transportDispatcher))
     else:
         snmpEngine.registerTransportDispatcher(
             transport.protoTransportDispatcher()
@@ -304,16 +330,16 @@ def addTransport(snmpEngine, transportDomain, transport):
         # here we note that we have created transportDispatcher automatically
         snmpEngine.setUserContext(automaticTransportDispatcher=0)
 
-    snmpEngine.transportDispatcher.registerTransport(transportDomain,
-                                                     transport)
+    snmpEngine.transportDispatcher.registerTransport(transportDomain, transport)
     automaticTransportDispatcher = snmpEngine.getUserContext(
         'automaticTransportDispatcher'
     )
     if automaticTransportDispatcher is not None:
         snmpEngine.setUserContext(
-            automaticTransportDispatcher=automaticTransportDispatcher+1
+            automaticTransportDispatcher=automaticTransportDispatcher + 1
         )
 
+
 def getTransport(snmpEngine, transportDomain):
     if not snmpEngine.transportDispatcher:
         return
@@ -322,6 +348,7 @@ def getTransport(snmpEngine, transportDomain):
     except error.PySnmpError:
         return
 
+
 def delTransport(snmpEngine, transportDomain):
     if not snmpEngine.transportDispatcher:
         return
@@ -342,28 +369,33 @@ def delTransport(snmpEngine, transportDomain):
             snmpEngine.delUserContext(automaticTransportDispatcher)
     return transport
 
+
 addSocketTransport = addTransport
 delSocketTransport = delTransport
 
+
 # VACM shortcuts
 
 def addContext(snmpEngine, contextName):
-    vacmContextEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
-        'SNMP-VIEW-BASED-ACM-MIB', 'vacmContextEntry'
-    )
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+    vacmContextEntry, = mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB', 'vacmContextEntry')
     tblIdx = vacmContextEntry.getInstIdFromIndices(contextName)
     snmpEngine.msgAndPduDsp.mibInstrumController.writeVars(
         ((vacmContextEntry.name + (1,) + tblIdx, contextName),)
     )
 
+
 def __cookVacmGroupInfo(snmpEngine, securityModel, securityName):
-    vacmSecurityToGroupEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
-        'SNMP-VIEW-BASED-ACM-MIB', 'vacmSecurityToGroupEntry'
-        )
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+    vacmSecurityToGroupEntry, = mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB',
+                                                         'vacmSecurityToGroupEntry')
     tblIdx = vacmSecurityToGroupEntry.getInstIdFromIndices(securityModel,
                                                            securityName)
     return vacmSecurityToGroupEntry, tblIdx
 
+
 def addVacmGroup(snmpEngine, groupName, securityModel, securityName):
     (vacmSecurityToGroupEntry,
      tblIdx) = __cookVacmGroupInfo(snmpEngine, securityModel, securityName)
@@ -377,6 +409,7 @@ def addVacmGroup(snmpEngine, groupName, securityModel, securityName):
          (vacmSecurityToGroupEntry.name + (5,) + tblIdx, 'createAndGo'))
     )
 
+
 def delVacmGroup(snmpEngine, securityModel, securityName):
     vacmSecurityToGroupEntry, tblIdx = __cookVacmGroupInfo(
         snmpEngine, securityModel, securityName
@@ -385,20 +418,24 @@ def delVacmGroup(snmpEngine, securityModel, securityName):
         ((vacmSecurityToGroupEntry.name + (5,) + tblIdx, 'destroy'),)
     )
 
+
 def __cookVacmAccessInfo(snmpEngine, groupName, contextName, securityModel,
                          securityLevel):
-    vacmAccessEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB', 'vacmAccessEntry')
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+    vacmAccessEntry, = mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB', 'vacmAccessEntry')
     tblIdx = vacmAccessEntry.getInstIdFromIndices(groupName, contextName,
                                                   securityModel, securityLevel)
     return vacmAccessEntry, tblIdx
 
+
 def addVacmAccess(snmpEngine, groupName, contextName, securityModel,
                   securityLevel, prefix, readView, writeView, notifyView):
     vacmAccessEntry, tblIdx = __cookVacmAccessInfo(snmpEngine, groupName,
                                                    contextName, securityModel,
                                                    securityLevel)
 
-    addContext(snmpEngine, contextName) # this is leaky
+    addContext(snmpEngine, contextName)  # this is leaky
 
     snmpEngine.msgAndPduDsp.mibInstrumController.writeVars(
         ((vacmAccessEntry.name + (9,) + tblIdx, 'destroy'),)
@@ -414,6 +451,7 @@ def addVacmAccess(snmpEngine, groupName, contextName, securityModel,
          (vacmAccessEntry.name + (9,) + tblIdx, 'createAndGo'))
     )
 
+
 def delVacmAccess(snmpEngine, groupName, contextName, securityModel,
                   securityLevel):
     vacmAccessEntry, tblIdx = __cookVacmAccessInfo(snmpEngine, groupName,
@@ -423,13 +461,17 @@ def delVacmAccess(snmpEngine, groupName, contextName, securityModel,
         ((vacmAccessEntry.name + (9,) + tblIdx, 'destroy'),)
     )
 
+
 def __cookVacmViewInfo(snmpEngine, viewName, subTree):
-    vacmViewTreeFamilyEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+    vacmViewTreeFamilyEntry, = mibBuilder.importSymbols(
         'SNMP-VIEW-BASED-ACM-MIB', 'vacmViewTreeFamilyEntry'
     )
     tblIdx = vacmViewTreeFamilyEntry.getInstIdFromIndices(viewName, subTree)
     return vacmViewTreeFamilyEntry, tblIdx
 
+
 def addVacmView(snmpEngine, viewName, viewType, subTree, mask):
     vacmViewTreeFamilyEntry, tblIdx = __cookVacmViewInfo(snmpEngine, viewName,
                                                          subTree)
@@ -444,6 +486,7 @@ def addVacmView(snmpEngine, viewName, viewType, subTree, mask):
          (vacmViewTreeFamilyEntry.name + (6,) + tblIdx, 'createAndGo'))
     )
 
+
 def delVacmView(snmpEngine, viewName, subTree):
     vacmViewTreeFamilyEntry, tblIdx = __cookVacmViewInfo(snmpEngine, viewName,
                                                          subTree)
@@ -451,15 +494,19 @@ def delVacmView(snmpEngine, viewName, subTree):
         ((vacmViewTreeFamilyEntry.name + (6,) + tblIdx, 'destroy'),)
     )
 
+
 # VACM simplicity wrappers
 
 def __cookVacmUserInfo(snmpEngine, securityModel, securityName, securityLevel):
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
     groupName = 'v-%s-%d' % (hash(securityName), securityModel)
-    SnmpSecurityLevel, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-FRAMEWORK-MIB', 'SnmpSecurityLevel')
+    SnmpSecurityLevel, = mibBuilder.importSymbols('SNMP-FRAMEWORK-MIB', 'SnmpSecurityLevel')
     securityLevel = SnmpSecurityLevel(securityLevel)
     return (groupName, securityLevel,
             'r' + groupName, 'w' + groupName, 'n' + groupName)
 
+
 def addVacmUser(snmpEngine, securityModel, securityName, securityLevel,
                 readSubTree=(), writeSubTree=(), notifySubTree=(),
                 contextName=null):
@@ -476,6 +523,7 @@ def addVacmUser(snmpEngine, securityModel, securityName, securityLevel,
     if notifySubTree:
         addVacmView(snmpEngine, notifyView, "included", notifySubTree, null)
 
+
 def delVacmUser(snmpEngine, securityModel, securityName, securityLevel,
                 readSubTree=(), writeSubTree=(), notifySubTree=()):
     (groupName, securityLevel, readView, writeView,
@@ -496,48 +544,59 @@ def delVacmUser(snmpEngine, securityModel, securityName, securityLevel,
             snmpEngine, notifyView, notifySubTree
         )
 
+
 # Obsolete shortcuts for add/delVacmUser() wrappers
 
 def addRoUser(snmpEngine, securityModel, securityName, securityLevel, subTree):
     addVacmUser(snmpEngine, securityModel, securityName,
                 securityLevel, subTree)
 
+
 def delRoUser(snmpEngine, securityModel, securityName, securityLevel, subTree):
     delVacmUser(snmpEngine, securityModel, securityName, securityLevel,
                 subTree)
 
+
 def addRwUser(snmpEngine, securityModel, securityName, securityLevel, subTree):
     addVacmUser(snmpEngine, securityModel, securityName, securityLevel,
                 subTree, subTree)
 
+
 def delRwUser(snmpEngine, securityModel, securityName, securityLevel, subTree):
     delVacmUser(snmpEngine, securityModel, securityName, securityLevel,
                 subTree, subTree)
 
+
 def addTrapUser(snmpEngine, securityModel, securityName,
                 securityLevel, subTree):
     addVacmUser(snmpEngine, securityModel, securityName, securityLevel,
                 (), (), subTree)
 
+
 def delTrapUser(snmpEngine, securityModel, securityName,
                 securityLevel, subTree):
     delVacmUser(snmpEngine, securityModel, securityName, securityLevel,
                 (), (), subTree)
 
+
 # Notification target setup
 
 def __cookNotificationTargetInfo(snmpEngine, notificationName, paramsName,
                                  filterSubtree=None):
-    snmpNotifyEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-NOTIFICATION-MIB', 'snmpNotifyEntry')
+    mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+    snmpNotifyEntry, = mibBuilder.importSymbols('SNMP-NOTIFICATION-MIB', 'snmpNotifyEntry')
     tblIdx1 = snmpNotifyEntry.getInstIdFromIndices(notificationName)
 
-    snmpNotifyFilterProfileEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-NOTIFICATION-MIB', 'snmpNotifyFilterProfileEntry')
+    snmpNotifyFilterProfileEntry, = mibBuilder.importSymbols('SNMP-NOTIFICATION-MIB',
+                                                             'snmpNotifyFilterProfileEntry')
     tblIdx2 = snmpNotifyFilterProfileEntry.getInstIdFromIndices(paramsName)
 
     profileName = '%s-filter' % hash(notificationName)
 
     if filterSubtree:
-        snmpNotifyFilterEntry, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-NOTIFICATION-MIB', 'snmpNotifyFilterEntry')
+        snmpNotifyFilterEntry, = mibBuilder.importSymbols('SNMP-NOTIFICATION-MIB',
+                                                          'snmpNotifyFilterEntry')
         tblIdx3 = snmpNotifyFilterEntry.getInstIdFromIndices(profileName,
                                                              filterSubtree)
     else:
@@ -547,6 +606,7 @@ def __cookNotificationTargetInfo(snmpEngine, notificationName, paramsName,
             snmpNotifyFilterProfileEntry, tblIdx2, profileName,
             snmpNotifyFilterEntry, tblIdx3)
 
+
 def addNotificationTarget(snmpEngine, notificationName, paramsName,
                           transportTag, notifyType=None, filterSubtree=None,
                           filterMask=None, filterType=None):
@@ -585,6 +645,7 @@ def addNotificationTarget(snmpEngine, notificationName, paramsName,
          (snmpNotifyFilterEntry.name + (5,) + tblIdx3, 'createAndGo'))
     )
 
+
 def delNotificationTarget(snmpEngine, notificationName, paramsName,
                           filterSubtree=None):
     (snmpNotifyEntry, tblIdx1, snmpNotifyFilterProfileEntry,
@@ -607,6 +668,7 @@ def delNotificationTarget(snmpEngine, notificationName, paramsName,
         ((snmpNotifyFilterEntry.name + (5,) + tblIdx3, 'destroy'),)
     )
 
+
 # rfc3415: A.1
 def setInitialVacmParameters(snmpEngine):
     # rfc3415: A.1.1 --> initial-semi-security-configuration
diff --git a/pysnmp/entity/engine.py b/pysnmp/entity/engine.py
index 76323d7b..868dbf37 100644
--- a/pysnmp/entity/engine.py
+++ b/pysnmp/entity/engine.py
@@ -9,10 +9,10 @@ import sys
 import tempfile
 from pysnmp.proto.rfc3412 import MsgAndPduDispatcher
 from pysnmp.proto.mpmod.rfc2576 import SnmpV1MessageProcessingModel, \
-     SnmpV2cMessageProcessingModel
+    SnmpV2cMessageProcessingModel
 from pysnmp.proto.mpmod.rfc3412 import SnmpV3MessageProcessingModel
 from pysnmp.proto.secmod.rfc2576 import SnmpV1SecurityModel, \
-     SnmpV2cSecurityModel
+    SnmpV2cSecurityModel
 from pysnmp.proto.secmod.rfc3414 import SnmpUSMSecurityModel
 from pysnmp.proto.acmod import rfc3415, void
 from pysnmp.entity import observer
@@ -21,6 +21,7 @@ from pysnmp import error
 
 __all__ = ['SnmpEngine']
 
+
 class SnmpEngine:
     """Creates SNMP engine object.
 
@@ -51,6 +52,7 @@ class SnmpEngine:
     >>>
 
     """
+
     def __init__(self, snmpEngineID=None, maxMessageSize=65507,
                  msgAndPduDsp=None):
         self.cache = {}
@@ -63,11 +65,11 @@ class SnmpEngine:
             self.msgAndPduDsp = msgAndPduDsp
         self.messageProcessingSubsystems = {
             SnmpV1MessageProcessingModel.messageProcessingModelID:
-            SnmpV1MessageProcessingModel(),
+                SnmpV1MessageProcessingModel(),
             SnmpV2cMessageProcessingModel.messageProcessingModelID:
-            SnmpV2cMessageProcessingModel(),
+                SnmpV2cMessageProcessingModel(),
             SnmpV3MessageProcessingModel.messageProcessingModelID:
-            SnmpV3MessageProcessingModel()
+                SnmpV3MessageProcessingModel()
         }
         self.securityModels = {
             SnmpV1SecurityModel.securityModelID: SnmpV1SecurityModel(),
@@ -85,11 +87,14 @@ class SnmpEngine:
             raise error.PySnmpError(
                 'MIB instrumentation does not yet exist'
             )
-        snmpEngineMaxMessageSize, = self.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
+        snmpEngineMaxMessageSize, = self.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+            '__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
         snmpEngineMaxMessageSize.syntax = snmpEngineMaxMessageSize.syntax.clone(maxMessageSize)
-        snmpEngineBoots, = self.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineBoots')
+        snmpEngineBoots, = self.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB',
+                                                                                           'snmpEngineBoots')
         snmpEngineBoots.syntax += 1
-        origSnmpEngineID, = self.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+        origSnmpEngineID, = self.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB',
+                                                                                            'snmpEngineID')
 
         if snmpEngineID is None:
             self.snmpEngineID = origSnmpEngineID.syntax
@@ -97,7 +102,8 @@ class SnmpEngine:
             origSnmpEngineID.syntax = origSnmpEngineID.syntax.clone(snmpEngineID)
             self.snmpEngineID = origSnmpEngineID.syntax
 
-            debug.logger & debug.flagApp and debug.logger('SnmpEngine: using custom SNMP Engine ID: %s' % self.snmpEngineID.prettyPrint())
+            debug.logger & debug.flagApp and debug.logger(
+                'SnmpEngine: using custom SNMP Engine ID: %s' % self.snmpEngineID.prettyPrint())
 
             # Attempt to make some of snmp Engine settings persistent.
             # This should probably be generalized as a non-volatile MIB store.
@@ -115,12 +121,12 @@ class SnmpEngine:
             f = os.path.join(persistentPath, 'boots')
             try:
                 snmpEngineBoots.syntax = snmpEngineBoots.syntax.clone(open(f).read())
-            except:
+            except Exception:
                 pass
 
             try:
                 snmpEngineBoots.syntax += 1
-            except:
+            except Exception:
                 snmpEngineBoots.syntax = snmpEngineBoots.syntax.clone(1)
 
             try:
@@ -128,14 +134,16 @@ class SnmpEngine:
                 os.write(fd, snmpEngineBoots.syntax.prettyPrint())
                 os.close(fd)
                 os.rename(fn, f)
-            except:
-                debug.logger & debug.flagApp and debug.logger('SnmpEngine: could not stored SNMP Engine Boots: %s' % sys.exc_info()[1])
+            except Exception:
+                debug.logger & debug.flagApp and debug.logger(
+                    'SnmpEngine: could not stored SNMP Engine Boots: %s' % sys.exc_info()[1])
             else:
-                debug.logger & debug.flagApp and debug.logger('SnmpEngine: stored SNMP Engine Boots: %s' % snmpEngineBoots.syntax.prettyPrint())
+                debug.logger & debug.flagApp and debug.logger(
+                    'SnmpEngine: stored SNMP Engine Boots: %s' % snmpEngineBoots.syntax.prettyPrint())
 
     def __repr__(self):
         return '%s(snmpEngineID=%r)' % \
-            (self.__class__.__name__, self.snmpEngineID)
+               (self.__class__.__name__, self.snmpEngineID)
 
     # Transport dispatcher bindings
 
@@ -193,4 +201,3 @@ class SnmpEngine:
             del self.cache['__%s' % arg]
         except KeyError:
             pass
-
diff --git a/pysnmp/entity/observer.py b/pysnmp/entity/observer.py
index c18546da..2e137129 100644
--- a/pysnmp/entity/observer.py
+++ b/pysnmp/entity/observer.py
@@ -6,6 +6,7 @@
 #
 from pysnmp import error
 
+
 class MetaObserver:
     """This is a simple facility for exposing internal SNMP Engine
        working details to pysnmp applications. These details are
@@ -21,6 +22,7 @@ class MetaObserver:
        to exist to functions that are at the same or deeper level of invocation
        relative to execution point specified.
     """
+
     def __init__(self):
         self.__observers = {}
         self.__contexts = {}
@@ -32,7 +34,7 @@ class MetaObserver:
         else:
             self.__contexts[cbFun] = kwargs.get('cbCtx')
         for execpoint in execpoints:
-            if not execpoint in self.__observers:
+            if execpoint not in self.__observers:
                 self.__observers[execpoint] = []
             self.__observers[execpoint].append(cbFun)
 
diff --git a/pysnmp/entity/rfc3413/cmdgen.py b/pysnmp/entity/rfc3413/cmdgen.py
index 200326f3..e174c379 100644
--- a/pysnmp/entity/rfc3413/cmdgen.py
+++ b/pysnmp/entity/rfc3413/cmdgen.py
@@ -17,16 +17,17 @@ getNextHandle = nextid.Integer(0x7fffffff)
 
 __null = univ.Null('')
 
+
 def getNextVarBinds(varBinds, origVarBinds=None):
     errorIndication = None
     idx = nonNulls = len(varBinds)
     rspVarBinds = []
     while idx:
-        idx = idx - 1
+        idx -= 1
         if varBinds[idx][1].tagSet in (rfc1905.NoSuchObject.tagSet,
                                        rfc1905.NoSuchInstance.tagSet,
                                        rfc1905.EndOfMibView.tagSet):
-            nonNulls = nonNulls - 1
+            nonNulls -= 1
         elif origVarBinds is not None:
             if v2c.ObjectIdentifier(origVarBinds[idx][0]).asTuple() >= varBinds[idx][0].asTuple():
                 errorIndication = errind.oidNotIncreasing
@@ -38,8 +39,10 @@ def getNextVarBinds(varBinds, origVarBinds=None):
 
     return errorIndication, rspVarBinds
 
+
 class CommandGenerator:
     _null = univ.Null('')
+
     def __init__(self):
         self.__pendingReqs = {}
 
@@ -64,16 +67,17 @@ class CommandGenerator:
 
         # 3.1.3
         if statusInformation:
-            debug.logger & debug.flagApp and debug.logger('processResponsePdu: sendPduHandle %s, statusInformation %s' % (sendPduHandle, statusInformation))
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponsePdu: sendPduHandle %s, statusInformation %s' % (sendPduHandle, statusInformation))
             errorIndication = statusInformation['errorIndication']
             # SNMP engine discovery will take extra retries, allow that
             if errorIndication in (errind.notInTimeWindow,
                                    errind.unknownEngineID) and \
-                                   origRetries == origRetryCount + 2 or \
-               errorIndication not in (errind.notInTimeWindow,
-                                       errind.unknownEngineID) and \
-                                   origRetries == origRetryCount:
-                debug.logger & debug.flagApp and debug.logger('processResponsePdu: sendPduHandle %s, retry count %d exceeded' % (sendPduHandle, origRetries))
+                    origRetries == origRetryCount + 2 or \
+                    errorIndication not in (errind.notInTimeWindow, errind.unknownEngineID) and \
+                    origRetries == origRetryCount:
+                debug.logger & debug.flagApp and debug.logger(
+                    'processResponsePdu: sendPduHandle %s, retry count %d exceeded' % (sendPduHandle, origRetries))
                 cbFun(snmpEngine, origSendRequestHandle,
                       statusInformation['errorIndication'], None, cbCtx)
                 return
@@ -99,19 +103,22 @@ class CommandGenerator:
 
             except StatusInformation:
                 statusInformation = sys.exc_info()[1]
-                debug.logger & debug.flagApp and debug.logger('processResponsePdu: origSendRequestHandle %s, _sendPdu() failed with %r' % (sendPduHandle, statusInformation))
+                debug.logger & debug.flagApp and debug.logger(
+                    'processResponsePdu: origSendRequestHandle %s, _sendPdu() failed with %r' % (
+                    sendPduHandle, statusInformation))
                 cbFun(snmpEngine, origSendRequestHandle,
                       statusInformation['errorIndication'],
                       None, cbCtx)
                 return
 
         if origMessageProcessingModel != messageProcessingModel or \
-           origSecurityModel != securityModel or \
-           origSecurityName != origSecurityName or \
-           origContextEngineId and origContextEngineId != contextEngineId or \
-           origContextName and origContextName != contextName or \
-           origPduVersion != pduVersion:
-            debug.logger & debug.flagApp and debug.logger('processResponsePdu: sendPduHandle %s, request/response data mismatch' % sendPduHandle)
+                origSecurityModel != securityModel or \
+                origSecurityName != origSecurityName or \
+                origContextEngineId and origContextEngineId != contextEngineId or \
+                origContextName and origContextName != contextName or \
+                origPduVersion != pduVersion:
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponsePdu: sendPduHandle %s, request/response data mismatch' % sendPduHandle)
 
             cbFun(snmpEngine, origSendRequestHandle,
                   'badResponse', None, cbCtx)
@@ -123,7 +130,8 @@ class CommandGenerator:
 
         # 3.1.2
         if v2c.apiPDU.getRequestID(PDU) != v2c.apiPDU.getRequestID(origPdu):
-            debug.logger & debug.flagApp and debug.logger('processResponsePdu: sendPduHandle %s, request-id/response-id mismatch' % sendPduHandle)
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponsePdu: sendPduHandle %s, request-id/response-id mismatch' % sendPduHandle)
             cbFun(snmpEngine, origSendRequestHandle,
                   'badResponse', None, cbCtx)
             return
@@ -138,9 +146,10 @@ class CommandGenerator:
          securityLevel) = config.getTargetInfo(snmpEngine, targetName)
 
         # Convert timeout in seconds into timeout in timer ticks
-        timeoutInTicks = float(timeout)/100/snmpEngine.transportDispatcher.getTimerResolution()
+        timeoutInTicks = float(timeout) / 100 / snmpEngine.transportDispatcher.getTimerResolution()
 
-        SnmpEngineID, SnmpAdminString = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-FRAMEWORK-MIB', 'SnmpEngineID', 'SnmpAdminString')
+        SnmpEngineID, SnmpAdminString = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+            'SNMP-FRAMEWORK-MIB', 'SnmpEngineID', 'SnmpAdminString')
 
         # Cast possible strings into bytes
         if contextEngineId:
@@ -176,13 +185,17 @@ class CommandGenerator:
             retryCount, 0
         )
 
-        debug.logger & debug.flagApp and debug.logger('sendPdu: sendPduHandle %s, timeout %d*10 ms/%d ticks, retry 0 of %d' % (sendPduHandle, timeout, timeoutInTicks, retryCount))
+        debug.logger & debug.flagApp and debug.logger(
+            'sendPdu: sendPduHandle %s, timeout %d*10 ms/%d ticks, retry 0 of %d' % (
+                sendPduHandle, timeout, timeoutInTicks, retryCount))
 
         return sendRequestHandle
 
+
 # backward compatibility stub
 CommandGeneratorBase = CommandGenerator
 
+
 class GetCommandGenerator(CommandGenerator):
     def processResponseVarBinds(self, snmpEngine, sendRequestHandle,
                                 errorIndication, PDU, cbCtx):
@@ -204,6 +217,7 @@ class GetCommandGenerator(CommandGenerator):
                             contextName, reqPDU, self.processResponseVarBinds,
                             (cbFun, cbCtx))
 
+
 class SetCommandGenerator(CommandGenerator):
     def processResponseVarBinds(self, snmpEngine, sendRequestHandle,
                                 errorIndication, PDU, cbCtx):
@@ -225,6 +239,7 @@ class SetCommandGenerator(CommandGenerator):
                             contextName, reqPDU,
                             self.processResponseVarBinds, (cbFun, cbCtx))
 
+
 class NextCommandGeneratorSingleRun(CommandGenerator):
     def processResponseVarBinds(self, snmpEngine, sendRequestHandle,
                                 errorIndication, PDU, cbCtx):
@@ -247,6 +262,7 @@ class NextCommandGeneratorSingleRun(CommandGenerator):
                             (targetName, contextEngineId, contextName,
                              reqPDU, cbFun, cbCtx))
 
+
 class NextCommandGenerator(NextCommandGeneratorSingleRun):
     def processResponseVarBinds(self, snmpEngine, sendRequestHandle,
                                 errorIndication, PDU, cbCtx):
@@ -272,11 +288,12 @@ class NextCommandGenerator(NextCommandGeneratorSingleRun):
                      v2c.apiPDU.getErrorStatus(PDU),
                      v2c.apiPDU.getErrorIndex(PDU, muteErrors=True),
                      varBindTable, cbCtx):
-            debug.logger & debug.flagApp and debug.logger('processResponseVarBinds: sendRequestHandle %s, app says to stop walking' % sendRequestHandle)
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponseVarBinds: sendRequestHandle %s, app says to stop walking' % sendRequestHandle)
             return  # app says enough
 
         if not varBinds:
-            return # no more objects available
+            return  # no more objects available
 
         v2c.apiPDU.setRequestID(reqPDU, v2c.getNextRequestID())
         v2c.apiPDU.setVarBinds(reqPDU, varBinds)
@@ -290,11 +307,13 @@ class NextCommandGenerator(NextCommandGeneratorSingleRun):
 
         except StatusInformation:
             statusInformation = sys.exc_info()[1]
-            debug.logger & debug.flagApp and debug.logger('sendVarBinds: sendPduHandle %s: sendPdu() failed with %r' % (sendRequestHandle, statusInformation))
+            debug.logger & debug.flagApp and debug.logger(
+                'sendVarBinds: sendPduHandle %s: sendPdu() failed with %r' % (sendRequestHandle, statusInformation))
             cbFun(snmpEngine, sendRequestHandle,
                   statusInformation['errorIndication'],
                   0, 0, (), cbCtx)
 
+
 class BulkCommandGeneratorSingleRun(CommandGenerator):
     def processResponseVarBinds(self, snmpEngine, sendRequestHandle,
                                 errorIndication, PDU, cbCtx):
@@ -324,6 +343,7 @@ class BulkCommandGeneratorSingleRun(CommandGenerator):
                              contextEngineId, contextName, reqPDU,
                              cbFun, cbCtx))
 
+
 class BulkCommandGenerator(BulkCommandGeneratorSingleRun):
     def processResponseVarBinds(self, snmpEngine, sendRequestHandle,
                                 errorIndication, PDU, cbCtx):
@@ -353,16 +373,16 @@ class BulkCommandGenerator(BulkCommandGeneratorSingleRun):
                      v2c.apiBulkPDU.getErrorStatus(PDU),
                      v2c.apiBulkPDU.getErrorIndex(PDU, muteErrors=True),
                      varBindTable, cbCtx):
-            debug.logger & debug.flagApp and debug.logger('processResponseVarBinds: sendRequestHandle %s, app says to stop walking' % sendRequestHandle)
-            return # app says enough
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponseVarBinds: sendRequestHandle %s, app says to stop walking' % sendRequestHandle)
+            return  # app says enough
 
         if not varBinds:
-            return # no more objects available
+            return  # no more objects available
 
         v2c.apiBulkPDU.setRequestID(reqPDU, v2c.getNextRequestID())
         v2c.apiBulkPDU.setVarBinds(reqPDU, varBinds)
 
-
         try:
             self.sendPdu(snmpEngine, targetName, contextEngineId,
                          contextName, reqPDU,
@@ -372,10 +392,13 @@ class BulkCommandGenerator(BulkCommandGeneratorSingleRun):
 
         except StatusInformation:
             statusInformation = sys.exc_info()[1]
-            debug.logger & debug.flagApp and debug.logger('processResponseVarBinds: sendPduHandle %s: _sendPdu() failed with %r' % (sendRequestHandle, statusInformation))
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponseVarBinds: sendPduHandle %s: _sendPdu() failed with %r' % (
+                    sendRequestHandle, statusInformation))
             cbFun(snmpEngine, sendRequestHandle,
                   statusInformation['errorIndication'], 0, 0, (), cbCtx)
 
+
 #
 # Obsolete, compatibility interfaces.
 #
@@ -386,12 +409,14 @@ def __sendReqCbFun(snmpEngine, sendRequestHandle, errorIndication,
     return cbFun(sendRequestHandle, errorIndication, errorStatus,
                  errorIndex, varBinds, cbCtx)
 
+
 def _sendReq(self, snmpEngine, targetName, varBinds, cbFun,
              cbCtx=None, contextEngineId=None, contextName=''):
     return self.sendVarBinds(snmpEngine, targetName, contextEngineId,
                              contextName, varBinds, __sendReqCbFun,
                              (cbFun, cbCtx))
 
+
 def _sendBulkReq(self, snmpEngine, targetName, nonRepeaters, maxRepetitions,
                  varBinds, cbFun, cbCtx=None, contextEngineId=None,
                  contextName=''):
@@ -399,6 +424,7 @@ def _sendBulkReq(self, snmpEngine, targetName, nonRepeaters, maxRepetitions,
                              contextName, nonRepeaters, maxRepetitions,
                              varBinds, __sendReqCbFun, (cbFun, cbCtx))
 
+
 # install compatibility wrappers
 GetCommandGenerator.sendReq = _sendReq
 SetCommandGenerator.sendReq = _sendReq
diff --git a/pysnmp/entity/rfc3413/cmdrsp.py b/pysnmp/entity/rfc3413/cmdrsp.py
index aa512170..60c64ad3 100644
--- a/pysnmp/entity/rfc3413/cmdrsp.py
+++ b/pysnmp/entity/rfc3413/cmdrsp.py
@@ -11,6 +11,7 @@ from pysnmp.proto.proxy import rfc2576
 import pysnmp.smi.error
 from pysnmp import debug
 
+
 # 3.2
 class CommandResponderBase:
     acmID = 3  # default MIB access control method to use
@@ -19,7 +20,7 @@ class CommandResponderBase:
     def __init__(self, snmpEngine, snmpContext):
         snmpEngine.msgAndPduDsp.registerContextEngineId(
             snmpContext.contextEngineId, self.pduTypes, self.processPdu
-            )
+        )
         self.snmpContext = snmpContext
         self.__pendingReqs = {}
 
@@ -44,7 +45,10 @@ class CommandResponderBase:
         v2c.apiPDU.setErrorIndex(PDU, errorIndex)
         v2c.apiPDU.setVarBinds(PDU, varBinds)
 
-        debug.logger & debug.flagApp and debug.logger('sendVarBinds: stateReference %s, errorStatus %s, errorIndex %s, varBinds %s' % (stateReference, errorStatus, errorIndex, varBinds))
+        debug.logger & debug.flagApp and debug.logger(
+            'sendVarBinds: stateReference %s, errorStatus %s, errorIndex %s, varBinds %s' % (
+            stateReference, errorStatus, errorIndex, varBinds)
+        )
 
         self.sendPdu(snmpEngine, stateReference, PDU)
 
@@ -79,8 +83,10 @@ class CommandResponderBase:
             )
 
         except error.StatusInformation:
-            debug.logger & debug.flagApp and debug.logger('sendPdu: stateReference %s, statusInformation %s' % (stateReference, sys.exc_info()[1]))
-            snmpSilentDrops, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpSilentDrops')
+            debug.logger & debug.flagApp and debug.logger(
+                'sendPdu: stateReference %s, statusInformation %s' % (stateReference, sys.exc_info()[1]))
+            snmpSilentDrops, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB',
+                                                                                                     'snmpSilentDrops')
             snmpSilentDrops.syntax += 1
 
     _getRequestType = rfc1905.GetRequestPDU.tagSet
@@ -105,7 +111,7 @@ class CommandResponderBase:
 
         # 3.2.1
         if PDU.tagSet not in rfc3411.readClassPDUs and \
-           PDU.tagSet not in rfc3411.writeClassPDUs:
+                PDU.tagSet not in rfc3411.writeClassPDUs:
             raise error.ProtocolError('Unexpected PDU class %s' % PDU.tagSet)
 
         # 3.2.2 --> no-op
@@ -125,16 +131,18 @@ class CommandResponderBase:
         varBinds = v2c.apiPDU.getVarBinds(PDU)
         errorStatus, errorIndex = 'noError', 0
 
-        debug.logger & debug.flagApp and debug.logger('processPdu: stateReference %s, varBinds %s' % (stateReference, varBinds))
+        debug.logger & debug.flagApp and debug.logger(
+            'processPdu: stateReference %s, varBinds %s' % (stateReference, varBinds))
 
         try:
             self.handleMgmtOperation(snmpEngine, stateReference,
-                                     contextName, PDU, 
+                                     contextName, PDU,
                                      (self.__verifyAccess, snmpEngine))
         # SNMPv2 SMI exceptions
         except pysnmp.smi.error.GenError:
             errorIndication = sys.exc_info()[1]
-            debug.logger & debug.flagApp and debug.logger('processPdu: stateReference %s, errorIndication %s' % (stateReference, errorIndication))
+            debug.logger & debug.flagApp and debug.logger(
+                'processPdu: stateReference %s, errorIndication %s' % (stateReference, errorIndication))
             if 'oid' in errorIndication:
                 # Request REPORT generation
                 statusInformation['oid'] = errorIndication['oid']
@@ -195,17 +203,19 @@ class CommandResponderBase:
         # Map ACM errors onto SMI ones
         except error.StatusInformation:
             statusInformation = sys.exc_info()[1]
-            debug.logger & debug.flagApp and debug.logger('__verifyAccess: name %s, statusInformation %s' % (name, statusInformation))
+            debug.logger & debug.flagApp and debug.logger(
+                '__verifyAccess: name %s, statusInformation %s' % (name, statusInformation))
             errorIndication = statusInformation['errorIndication']
             # 3.2.5...
             if errorIndication == errind.noSuchView or \
-               errorIndication == errind.noAccessEntry or \
-               errorIndication == errind.noGroupName:
+                    errorIndication == errind.noAccessEntry or \
+                    errorIndication == errind.noGroupName:
                 raise pysnmp.smi.error.AuthorizationError(name=name, idx=idx)
             elif errorIndication == errind.otherError:
                 raise pysnmp.smi.error.GenError(name=name, idx=idx)
             elif errorIndication == errind.noSuchContext:
-                snmpUnknownContexts, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-TARGET-MIB', 'snmpUnknownContexts')
+                snmpUnknownContexts, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+                    '__SNMP-TARGET-MIB', 'snmpUnknownContexts')
                 snmpUnknownContexts.syntax += 1
                 # Request REPORT generation
                 raise pysnmp.smi.error.GenError(name=name, idx=idx,
@@ -218,11 +228,12 @@ class CommandResponderBase:
         else:
             # rfc2576: 4.1.2.1
             if securityModel == 1 and syntax is not None and \
-                   self._counter64Type == syntax.getTagSet() and \
-                   self._getNextRequestType == pduType:
+                    self._counter64Type == syntax.getTagSet() and \
+                    self._getNextRequestType == pduType:
                 # This will cause MibTree to skip this OID-value
                 raise pysnmp.smi.error.NoAccessError(name=name, idx=idx)
 
+
 class GetCommandResponder(CommandResponderBase):
     pduTypes = (rfc1905.GetRequestPDU.tagSet,)
 
@@ -236,6 +247,7 @@ class GetCommandResponder(CommandResponderBase):
                           mgmtFun(v2c.apiPDU.getVarBinds(PDU), (acFun, acCtx)))
         self.releaseStateInformation(stateReference)
 
+
 class NextCommandResponder(CommandResponderBase):
     pduTypes = (rfc1905.GetNextRequestPDU.tagSet,)
 
@@ -257,6 +269,7 @@ class NextCommandResponder(CommandResponderBase):
                 break
         self.releaseStateInformation(stateReference)
 
+
 class BulkCommandResponder(CommandResponderBase):
     pduTypes = (rfc1905.GetBulkRequestPDU.tagSet,)
     maxVarBinds = 64
@@ -276,10 +289,10 @@ class BulkCommandResponder(CommandResponderBase):
 
         N = min(int(nonRepeaters), len(reqVarBinds))
         M = int(maxRepetitions)
-        R = max(len(reqVarBinds)-N, 0)
+        R = max(len(reqVarBinds) - N, 0)
 
         if R:
-            M = min(M, self.maxVarBinds/R)
+            M = min(M, self.maxVarBinds / R)
 
         debug.logger & debug.flagApp and debug.logger('handleMgmtOperation: N %d, M %d, R %d' % (N, M, R))
 
@@ -294,7 +307,7 @@ class BulkCommandResponder(CommandResponderBase):
         while M and R:
             rspVarBinds.extend(mgmtFun(varBinds, (acFun, acCtx)))
             varBinds = rspVarBinds[-R:]
-            M = M - 1
+            M -= 1
 
         if len(rspVarBinds):
             self.sendVarBinds(snmpEngine, stateReference, 0, 0, rspVarBinds)
@@ -302,6 +315,7 @@ class BulkCommandResponder(CommandResponderBase):
         else:
             raise pysnmp.smi.error.SmiError()
 
+
 class SetCommandResponder(CommandResponderBase):
     pduTypes = (rfc1905.SetRequestPDU.tagSet,)
 
diff --git a/pysnmp/entity/rfc3413/config.py b/pysnmp/entity/rfc3413/config.py
index adbf6dae..a73f9168 100644
--- a/pysnmp/entity/rfc3413/config.py
+++ b/pysnmp/entity/rfc3413/config.py
@@ -7,6 +7,7 @@
 from pysnmp.smi.error import SmiError, NoSuchInstanceError
 from pysnmp.entity import config
 
+
 def getTargetAddr(snmpEngine, snmpTargetAddrName):
     mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
 
@@ -30,10 +31,10 @@ def getTargetAddr(snmpEngine, snmpTargetAddrName):
          snmpTargetAddrTimeout,
          snmpTargetAddrRetryCount,
          snmpTargetAddrParams) = mibBuilder.importSymbols(
-             'SNMP-TARGET-MIB', 'snmpTargetAddrTDomain',
-             'snmpTargetAddrTAddress', 'snmpTargetAddrTimeout',
-             'snmpTargetAddrRetryCount', 'snmpTargetAddrParams'
-         )
+            'SNMP-TARGET-MIB', 'snmpTargetAddrTDomain',
+            'snmpTargetAddrTAddress', 'snmpTargetAddrTimeout',
+            'snmpTargetAddrRetryCount', 'snmpTargetAddrParams'
+        )
         snmpSourceAddrTAddress, = mibBuilder.importSymbols('PYSNMP-SOURCE-MIB', 'snmpSourceAddrTAddress')
 
         tblIdx = snmpTargetAddrEntry.getInstIdFromIndices(snmpTargetAddrName)
@@ -63,12 +64,14 @@ def getTargetAddr(snmpEngine, snmpTargetAddrName):
         transport = snmpEngine.transportDispatcher.getTransport(snmpTargetAddrTDomain)
 
         if snmpTargetAddrTDomain[:len(config.snmpUDPDomain)] == config.snmpUDPDomain:
-            SnmpUDPAddress, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMPv2-TM', 'SnmpUDPAddress')
+            SnmpUDPAddress, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMPv2-TM',
+                                                                                                    'SnmpUDPAddress')
             snmpTargetAddrTAddress = transport.addressType(
                 SnmpUDPAddress(snmpTargetAddrTAddress)
             ).setLocalAddress(SnmpUDPAddress(snmpSourceAddrTAddress))
         elif snmpTargetAddrTDomain[:len(config.snmpUDP6Domain)] == config.snmpUDP6Domain:
-            TransportAddressIPv6, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('TRANSPORT-ADDRESS-MIB', 'TransportAddressIPv6')
+            TransportAddressIPv6, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+                'TRANSPORT-ADDRESS-MIB', 'TransportAddressIPv6')
             snmpTargetAddrTAddress = transport.addressType(
                 TransportAddressIPv6(snmpTargetAddrTAddress)
             ).setLocalAddress(TransportAddressIPv6(snmpSourceAddrTAddress))
@@ -111,10 +114,10 @@ def getTargetParams(snmpEngine, paramsName):
         (snmpTargetParamsMPModel, snmpTargetParamsSecurityModel,
          snmpTargetParamsSecurityName,
          snmpTargetParamsSecurityLevel) = mibBuilder.importSymbols(
-             'SNMP-TARGET-MIB', 'snmpTargetParamsMPModel',
-             'snmpTargetParamsSecurityModel', 'snmpTargetParamsSecurityName',
-             'snmpTargetParamsSecurityLevel'
-         )
+            'SNMP-TARGET-MIB', 'snmpTargetParamsMPModel',
+            'snmpTargetParamsSecurityModel', 'snmpTargetParamsSecurityName',
+            'snmpTargetParamsSecurityLevel'
+        )
 
         tblIdx = snmpTargetParamsEntry.getInstIdFromIndices(paramsName)
 
@@ -143,6 +146,7 @@ def getTargetParams(snmpEngine, paramsName):
 
     return nameToParamsMap[paramsName]
 
+
 def getTargetInfo(snmpEngine, snmpTargetAddrName):
     # Transport endpoint
     (snmpTargetAddrTDomain,
@@ -162,6 +166,7 @@ def getTargetInfo(snmpEngine, snmpTargetAddrName):
             snmpTargetParamsMPModel, snmpTargetParamsSecurityModel,
             snmpTargetParamsSecurityName, snmpTargetParamsSecurityLevel)
 
+
 def getNotificationInfo(snmpEngine, notificationTarget):
     mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
 
@@ -206,6 +211,7 @@ def getNotificationInfo(snmpEngine, notificationTarget):
 
     return targetToNotifyMap[notificationTarget]
 
+
 def getTargetNames(snmpEngine, tag):
     mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
 
@@ -226,9 +232,9 @@ def getTargetNames(snmpEngine, tag):
 
         (SnmpTagValue, snmpTargetAddrName,
          snmpTargetAddrTagList) = mibBuilder.importSymbols(
-             'SNMP-TARGET-MIB', 'SnmpTagValue', 'snmpTargetAddrName',
-             'snmpTargetAddrTagList'
-         )
+            'SNMP-TARGET-MIB', 'SnmpTagValue', 'snmpTargetAddrName',
+            'snmpTargetAddrTagList'
+        )
         mibNode = snmpTargetAddrTagList
         while True:
             try:
diff --git a/pysnmp/entity/rfc3413/context.py b/pysnmp/entity/rfc3413/context.py
index 512c93fb..e0b73ef4 100644
--- a/pysnmp/entity/rfc3413/context.py
+++ b/pysnmp/entity/rfc3413/context.py
@@ -9,9 +9,11 @@ from pyasn1.compat.octets import null
 from pysnmp import error
 from pysnmp import debug
 
+
 class SnmpContext:
     def __init__(self, snmpEngine, contextEngineId=None):
-        snmpEngineId, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+        snmpEngineId, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB',
+                                                                                              'snmpEngineID')
         if contextEngineId is None:
             # Default to local snmpEngineId
             self.contextEngineId = snmpEngineId.syntax
@@ -19,16 +21,17 @@ class SnmpContext:
             self.contextEngineId = snmpEngineId.syntax.clone(contextEngineId)
         debug.logger & debug.flagIns and debug.logger('SnmpContext: contextEngineId \"%r\"' % (self.contextEngineId,))
         self.contextNames = {
-            null: snmpEngine.msgAndPduDsp.mibInstrumController # Default name
-            }
+            null: snmpEngine.msgAndPduDsp.mibInstrumController  # Default name
+        }
 
     def registerContextName(self, contextName, mibInstrum=None):
         contextName = univ.OctetString(contextName).asOctets()
         if contextName in self.contextNames:
             raise error.PySnmpError(
                 'Duplicate contextName %s' % contextName
-                )
-        debug.logger & debug.flagIns and debug.logger('registerContextName: registered contextName %r, mibInstrum %r' % (contextName, mibInstrum))
+            )
+        debug.logger & debug.flagIns and debug.logger(
+            'registerContextName: registered contextName %r, mibInstrum %r' % (contextName, mibInstrum))
         if mibInstrum is None:
             self.contextNames[contextName] = self.contextNames[null]
         else:
@@ -37,7 +40,8 @@ class SnmpContext:
     def unregisterContextName(self, contextName):
         contextName = univ.OctetString(contextName).asOctets()
         if contextName in self.contextNames:
-            debug.logger & debug.flagIns and debug.logger('unregisterContextName: unregistered contextName %r' % contextName)
+            debug.logger & debug.flagIns and debug.logger(
+                'unregisterContextName: unregistered contextName %r' % contextName)
             del self.contextNames[contextName]
 
     def getMibInstrum(self, contextName=null):
@@ -46,7 +50,8 @@ class SnmpContext:
             debug.logger & debug.flagIns and debug.logger('getMibInstrum: contextName %r not registered' % contextName)
             raise error.PySnmpError(
                 'Missing contextName %s' % contextName
-                )
+            )
         else:
-            debug.logger & debug.flagIns and debug.logger('getMibInstrum: contextName %r, mibInstum %r' % (contextName, self.contextNames[contextName]))
+            debug.logger & debug.flagIns and debug.logger(
+                'getMibInstrum: contextName %r, mibInstum %r' % (contextName, self.contextNames[contextName]))
             return self.contextNames[contextName]
diff --git a/pysnmp/entity/rfc3413/mibvar.py b/pysnmp/entity/rfc3413/mibvar.py
index 7cc46123..fdcef9f5 100644
--- a/pysnmp/entity/rfc3413/mibvar.py
+++ b/pysnmp/entity/rfc3413/mibvar.py
@@ -10,16 +10,17 @@
 from pyasn1.type import univ
 from pysnmp.smi.error import NoSuchObjectError
 
+
 # Name
 
 def mibNameToOid(mibView, name):
     if isinstance(name[0], tuple):
         f = lambda x='', y='': (x, y)
         modName, symName = f(*name[0])
-        if modName: # load module if needed
+        if modName:  # load module if needed
             mibView.mibBuilder.loadModules(modName)
         else:
-            mibView.mibBuilder.loadModules() # load all (slow)
+            mibView.mibBuilder.loadModules()  # load all (slow)
         if symName:
             oid, label, suffix = mibView.getNodeNameByDesc(symName, modName)
         else:
@@ -28,12 +29,12 @@ def mibNameToOid(mibView, name):
         modName, symName, _s = mibView.getNodeLocation(oid)
         mibNode, = mibView.mibBuilder.importSymbols(
             modName, symName
-            )
-        if hasattr(mibNode, 'createTest'): # table column XXX
+        )
+        if hasattr(mibNode, 'createTest'):  # table column XXX
             modName, symName, _s = mibView.getNodeLocation(oid[:-1])
             rowNode, = mibView.mibBuilder.importSymbols(modName, symName)
             return oid, rowNode.getInstIdFromIndices(*suffix)
-        else: # scalar or incomplete spec
+        else:  # scalar or incomplete spec
             return oid, suffix
     elif not isinstance(name, tuple):
         name = tuple(univ.ObjectIdentifier(name))
@@ -42,8 +43,10 @@ def mibNameToOid(mibView, name):
 
     return oid, suffix
 
+
 __scalarSuffix = (univ.Integer(0),)
 
+
 def oidToMibName(mibView, oid):
     if not isinstance(oid, tuple):
         oid = tuple(univ.ObjectIdentifier(oid))
@@ -51,27 +54,29 @@ def oidToMibName(mibView, oid):
     modName, symName, __suffix = mibView.getNodeLocation(_oid)
     mibNode, = mibView.mibBuilder.importSymbols(
         modName, symName
-        )
-    if hasattr(mibNode, 'createTest'): # table column
+    )
+    if hasattr(mibNode, 'createTest'):  # table column
         __modName, __symName, __s = mibView.getNodeLocation(_oid[:-1])
         rowNode, = mibView.mibBuilder.importSymbols(__modName, __symName)
         return (symName, modName), rowNode.getIndicesFromInstId(suffix)
-    elif not suffix: # scalar
+    elif not suffix:  # scalar
         return (symName, modName), suffix
-    elif suffix == (0,): # scalar
+    elif suffix == (0,):  # scalar
         return (symName, modName), __scalarSuffix
     else:
         raise NoSuchObjectError(
-            str='No MIB registered that defines %s object, closest known parent is %s (%s::%s)' % (univ.ObjectIdentifier(oid), univ.ObjectIdentifier(mibNode.name), modName, symName)
-            )
+            str='No MIB registered that defines %s object, closest known parent is %s (%s::%s)' % (
+                univ.ObjectIdentifier(oid), univ.ObjectIdentifier(mibNode.name), modName, symName)
+        )
+
 
 # Value
 
 def cloneFromMibValue(mibView, modName, symName, value):
     mibNode, = mibView.mibBuilder.importSymbols(
         modName, symName
-        )
-    if hasattr(mibNode, 'syntax'): # scalar
+    )
+    if hasattr(mibNode, 'syntax'):  # scalar
         return mibNode.syntax.clone(value)
     else:
-        return   # identifier
+        return  # identifier
diff --git a/pysnmp/entity/rfc3413/ntforg.py b/pysnmp/entity/rfc3413/ntforg.py
index 66d7f33d..c9bd69c4 100644
--- a/pysnmp/entity/rfc3413/ntforg.py
+++ b/pysnmp/entity/rfc3413/ntforg.py
@@ -17,8 +17,10 @@ from pysnmp import debug
 
 getNextHandle = nextid.Integer(0x7fffffff)
 
+
 class NotificationOriginator:
     acmID = 3  # default MIB access control method to use
+
     def __init__(self, snmpContext=None):
         self.__pendingReqs = {}
         self.__pendingNotifications = {}
@@ -43,15 +45,19 @@ class NotificationOriginator:
         snmpEngine.transportDispatcher.jobFinished(id(self))
 
         if statusInformation:
-            debug.logger & debug.flagApp and debug.logger('processResponsePdu: sendRequestHandle %s, sendPduHandle %s statusInformation %s' % (sendRequestHandle, sendPduHandle, statusInformation))
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponsePdu: sendRequestHandle %s, sendPduHandle %s statusInformation %s' % (
+                    sendRequestHandle, sendPduHandle, statusInformation))
             if origRetries == origRetryCount:
-                debug.logger & debug.flagApp and debug.logger('processResponsePdu: sendRequestHandle %s, sendPduHandle %s retry count %d exceeded' % (sendRequestHandle, sendPduHandle, origRetries))
+                debug.logger & debug.flagApp and debug.logger(
+                    'processResponsePdu: sendRequestHandle %s, sendPduHandle %s retry count %d exceeded' % (
+                        sendRequestHandle, sendPduHandle, origRetries))
                 cbFun(snmpEngine, sendRequestHandle,
                       statusInformation['errorIndication'], None, cbCtx)
                 return
 
             # Convert timeout in seconds into timeout in timer ticks
-            timeoutInTicks = float(origTimeout)/100/snmpEngine.transportDispatcher.getTimerResolution()
+            timeoutInTicks = float(origTimeout) / 100 / snmpEngine.transportDispatcher.getTimerResolution()
 
             # User-side API assumes SMIv2
             if messageProcessingModel == 0:
@@ -73,14 +79,18 @@ class NotificationOriginator:
                 )
             except error.StatusInformation:
                 statusInformation = sys.exc_info()[1]
-                debug.logger & debug.flagApp and debug.logger('processResponsePdu: sendRequestHandle %s: sendPdu() failed with %r ' % (sendRequestHandle, statusInformation))
+                debug.logger & debug.flagApp and debug.logger(
+                    'processResponsePdu: sendRequestHandle %s: sendPdu() failed with %r ' % (
+                        sendRequestHandle, statusInformation))
                 cbFun(snmpEngine, sendRequestHandle,
                       statusInformation['errorIndication'], None, cbCtx)
                 return
 
             snmpEngine.transportDispatcher.jobStarted(id(self))
 
-            debug.logger & debug.flagApp and debug.logger('processResponsePdu: sendRequestHandle %s, sendPduHandle %s, timeout %d, retry %d of %d' % (sendRequestHandle, sendPduHandle, origTimeout, origRetries, origRetryCount))
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponsePdu: sendRequestHandle %s, sendPduHandle %s, timeout %d, retry %d of %d' % (
+                    sendRequestHandle, sendPduHandle, origTimeout, origRetries, origRetryCount))
 
             # 3.3.6b
             self.__pendingReqs[sendPduHandle] = (
@@ -118,7 +128,7 @@ class NotificationOriginator:
         # 3.3.5
         if reqPDU.tagSet in rfc3411.confirmedClassPDUs:
             # Convert timeout in seconds into timeout in timer ticks
-            timeoutInTicks = float(timeout)/100/snmpEngine.transportDispatcher.getTimerResolution()
+            timeoutInTicks = float(timeout) / 100 / snmpEngine.transportDispatcher.getTimerResolution()
 
             sendRequestHandle = getNextHandle()
 
@@ -131,7 +141,8 @@ class NotificationOriginator:
                 self.processResponsePdu, (sendRequestHandle, cbFun, cbCtx)
             )
 
-            debug.logger & debug.flagApp and debug.logger('sendPdu: sendPduHandle %s, timeout %d' % (sendPduHandle, timeout))
+            debug.logger & debug.flagApp and debug.logger(
+                'sendPdu: sendPduHandle %s, timeout %d' % (sendPduHandle, timeout))
 
             # 3.3.6b
             self.__pendingReqs[sendPduHandle] = (
@@ -160,10 +171,14 @@ class NotificationOriginator:
 
         self.__pendingNotifications[notificationHandle].remove(sendRequestHandle)
 
-        debug.logger & debug.flagApp and debug.logger('processResponseVarBinds: notificationHandle %s, sendRequestHandle %s, errorIndication %s, pending requests %s' % (notificationHandle, sendRequestHandle, errorIndication, self.__pendingNotifications[notificationHandle]))
+        debug.logger & debug.flagApp and debug.logger(
+            'processResponseVarBinds: notificationHandle %s, sendRequestHandle %s, errorIndication %s, pending requests %s' % (
+                notificationHandle, sendRequestHandle, errorIndication, self.__pendingNotifications[notificationHandle]))
 
         if not self.__pendingNotifications[notificationHandle]:
-            debug.logger & debug.flagApp and debug.logger('processResponseVarBinds: notificationHandle %s, sendRequestHandle %s -- completed' % (notificationHandle, sendRequestHandle))
+            debug.logger & debug.flagApp and debug.logger(
+                'processResponseVarBinds: notificationHandle %s, sendRequestHandle %s -- completed' % (
+                    notificationHandle, sendRequestHandle))
             del self.__pendingNotifications[notificationHandle]
             cbFun(snmpEngine, sendRequestHandle, errorIndication,
                   pdu and v2c.apiPDU.getErrorStatus(pdu) or 0,
@@ -177,10 +192,13 @@ class NotificationOriginator:
     #
     def sendVarBinds(self, snmpEngine, notificationTarget, contextEngineId,
                      contextName, varBinds=(), cbFun=None, cbCtx=None):
-        debug.logger & debug.flagApp and debug.logger('sendVarBinds: notificationTarget %s, contextEngineId %s, contextName "%s", varBinds %s' % (notificationTarget, contextEngineId or '<default>', contextName, varBinds))
+        debug.logger & debug.flagApp and debug.logger(
+            'sendVarBinds: notificationTarget %s, contextEngineId %s, contextName "%s", varBinds %s' % (
+                notificationTarget, contextEngineId or '<default>', contextName, varBinds))
 
         if contextName:
-            __SnmpAdminString, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('SNMP-FRAMEWORK-MIB', 'SnmpAdminString')
+            __SnmpAdminString, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+                'SNMP-FRAMEWORK-MIB', 'SnmpAdminString')
             contextName = __SnmpAdminString(contextName)
 
         # 3.3
@@ -188,12 +206,16 @@ class NotificationOriginator:
 
         notificationHandle = getNextHandle()
 
-        debug.logger & debug.flagApp and debug.logger('sendVarBinds: notificationHandle %s, notifyTag %s, notifyType %s' % (notificationHandle, notifyTag, notifyType))
+        debug.logger & debug.flagApp and debug.logger(
+            'sendVarBinds: notificationHandle %s, notifyTag %s, notifyType %s' % (
+                notificationHandle, notifyTag, notifyType))
 
         varBinds = [(v2c.ObjectIdentifier(x), y) for x, y in varBinds]
 
         # 3.3.2 & 3.3.3
-        snmpTrapOID, sysUpTime = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpTrapOID', 'sysUpTime')
+        snmpTrapOID, sysUpTime = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB',
+                                                                                                       'snmpTrapOID',
+                                                                                                       'sysUpTime')
 
         for idx in range(len(varBinds)):
             if idx and varBinds[idx][0] == sysUpTime.getName():
@@ -211,6 +233,8 @@ class NotificationOriginator:
             varBinds.insert(1, (v2c.ObjectIdentifier(snmpTrapOID.getName()),
                                 snmpTrapOID.getSyntax()))
 
+        sendRequestHandle = -1
+
         debug.logger & debug.flagApp and debug.logger('sendVarBinds: final varBinds %s' % (varBinds,))
 
         for targetAddrName in config.getTargetNames(snmpEngine, notifyTag):
@@ -221,13 +245,16 @@ class NotificationOriginator:
              securityLevel) = config.getTargetParams(snmpEngine, params)
 
             # 3.3.1 XXX
-# XXX filtering's yet to be implemented
-#             filterProfileName = config.getNotifyFilterProfile(params)
+            # XXX filtering's yet to be implemented
+            #             filterProfileName = config.getNotifyFilterProfile(params)
 
-#             (filterSubtree, filterMask,
-#              filterType) = config.getNotifyFilter(filterProfileName)
+            #             (filterSubtree, filterMask,
+            #              filterType) = config.getNotifyFilter(filterProfileName)
 
-            debug.logger & debug.flagApp and debug.logger('sendVarBinds: notificationHandle %s, notifyTag %s yields: transportDomain %s, transportAddress %r, securityModel %s, securityName %s, securityLevel %s' % (notificationHandle, notifyTag, transportDomain, transportAddress, securityModel, securityName, securityLevel))
+            debug.logger & debug.flagApp and debug.logger(
+                'sendVarBinds: notificationHandle %s, notifyTag %s yields: transportDomain %s, transportAddress %r, securityModel %s, securityName %s, securityLevel %s' % (
+                    notificationHandle, notifyTag, transportDomain, transportAddress, securityModel,
+                    securityName, securityLevel))
 
             for varName, varVal in varBinds:
                 if varName in (sysUpTime.name, snmpTrapOID.name):
@@ -238,10 +265,13 @@ class NotificationOriginator:
                         securityLevel, 'notify', contextName, varName
                     )
 
-                    debug.logger & debug.flagApp and debug.logger('sendVarBinds: ACL succeeded for OID %s securityName %s' % (varName, securityName))
+                    debug.logger & debug.flagApp and debug.logger(
+                        'sendVarBinds: ACL succeeded for OID %s securityName %s' % (varName, securityName))
 
                 except error.StatusInformation:
-                    debug.logger & debug.flagApp and debug.logger('sendVarBinds: ACL denied access for OID %s securityName %s, droppping notification' % (varName, securityName))
+                    debug.logger & debug.flagApp and debug.logger(
+                        'sendVarBinds: ACL denied access for OID %s securityName %s, droppping notification' % (
+                            varName, securityName))
                     return
 
             # 3.3.4
@@ -265,9 +295,11 @@ class NotificationOriginator:
 
             except error.StatusInformation:
                 statusInformation = sys.exc_info()[1]
-                debug.logger & debug.flagApp and debug.logger('sendVarBinds: sendRequestHandle %s: sendPdu() failed with %r' % (sendRequestHandle, statusInformation))
+                debug.logger & debug.flagApp and debug.logger(
+                    'sendVarBinds: sendRequestHandle %s: sendPdu() failed with %r' % (
+                        sendRequestHandle, statusInformation))
                 if notificationHandle not in self.__pendingNotifications or \
-                       not self.__pendingNotifications[notificationHandle]:
+                        not self.__pendingNotifications[notificationHandle]:
                     if notificationHandle in self.__pendingNotifications:
                         del self.__pendingNotifications[notificationHandle]
                     if cbFun:
@@ -276,17 +308,22 @@ class NotificationOriginator:
                               cbCtx)
                 return notificationHandle
 
-            debug.logger & debug.flagApp and debug.logger('sendVarBinds: notificationHandle %s, sendRequestHandle %s, timeout %d' % (notificationHandle, sendRequestHandle, timeout))
+            debug.logger & debug.flagApp and debug.logger(
+                'sendVarBinds: notificationHandle %s, sendRequestHandle %s, timeout %d' % (
+                    notificationHandle, sendRequestHandle, timeout))
 
             if notifyType == 2:
                 if notificationHandle not in self.__pendingNotifications:
                     self.__pendingNotifications[notificationHandle] = set()
                 self.__pendingNotifications[notificationHandle].add(sendRequestHandle)
 
-        debug.logger & debug.flagApp and debug.logger('sendVarBinds: notificationHandle %s, sendRequestHandle %s, notification(s) sent' % (notificationHandle, sendRequestHandle))
+        debug.logger & debug.flagApp and debug.logger(
+            'sendVarBinds: notificationHandle %s, sendRequestHandle %s, notification(s) sent' % (
+                notificationHandle, sendRequestHandle))
 
         return notificationHandle
 
+
 #
 # Obsolete, compatibility interfaces.
 #
@@ -303,6 +340,7 @@ def _sendNotificationCbFun(snmpEngine, sendRequestHandle, errorIndication,
         # a backward compatible way of calling user function
         cbFun(sendRequestHandle, errorIndication, cbCtx)
 
+
 def _sendNotification(self, snmpEngine, notificationTarget, notificationName,
                       additionalVarBinds=(), cbFun=None, cbCtx=None,
                       contextName=null, instanceIndex=None):
@@ -342,6 +380,7 @@ def _sendNotification(self, snmpEngine, notificationTarget, notificationName,
                              contextName, varBinds + list(additionalVarBinds),
                              _sendNotificationCbFun, (cbFun, cbCtx))
 
+
 # install compatibility wrapper
 NotificationOriginator.sendNotification = _sendNotification
 
diff --git a/pysnmp/entity/rfc3413/ntfrcv.py b/pysnmp/entity/rfc3413/ntfrcv.py
index 2b79f9f1..55b2841c 100644
--- a/pysnmp/entity/rfc3413/ntfrcv.py
+++ b/pysnmp/entity/rfc3413/ntfrcv.py
@@ -11,6 +11,7 @@ from pysnmp.proto.api import v1, v2c  # backend is always SMIv2 compliant
 from pysnmp.proto.proxy import rfc2576
 from pysnmp import debug
 
+
 # 3.4
 class NotificationReceiver:
     pduTypes = (v1.TrapPDU.tagSet, v2c.SNMPv2TrapPDU.tagSet,
@@ -18,7 +19,7 @@ class NotificationReceiver:
 
     def __init__(self, snmpEngine, cbFun, cbCtx=None):
         snmpEngine.msgAndPduDsp.registerContextEngineId(
-            null, self.pduTypes, self.processPdu # '' is a wildcard
+            null, self.pduTypes, self.processPdu  # '' is a wildcard
         )
         self.__cbFunVer = 0
         self.__cbFun = cbFun
@@ -46,7 +47,8 @@ class NotificationReceiver:
         errorIndex = 0
         varBinds = v2c.apiPDU.getVarBinds(PDU)
 
-        debug.logger & debug.flagApp and debug.logger('processPdu: stateReference %s, varBinds %s' % (stateReference, varBinds))
+        debug.logger & debug.flagApp and debug.logger(
+            'processPdu: stateReference %s, varBinds %s' % (stateReference, varBinds))
 
         # 3.4
         if PDU.tagSet in rfc3411.confirmedClassPDUs:
@@ -59,7 +61,8 @@ class NotificationReceiver:
             v2c.apiPDU.setErrorIndex(rspPDU, errorIndex)
             v2c.apiPDU.setVarBinds(rspPDU, varBinds)
 
-            debug.logger & debug.flagApp and debug.logger('processPdu: stateReference %s, confirm PDU %s' % (stateReference, rspPDU.prettyPrint()))
+            debug.logger & debug.flagApp and debug.logger(
+                'processPdu: stateReference %s, confirm PDU %s' % (stateReference, rspPDU.prettyPrint()))
 
             # Agent-side API complies with SMIv2
             if messageProcessingModel == 0:
@@ -76,8 +79,10 @@ class NotificationReceiver:
                     stateReference, statusInformation)
 
             except error.StatusInformation:
-                debug.logger & debug.flagApp and debug.logger('processPdu: stateReference %s, statusInformation %s' % (stateReference, sys.exc_info()[1]))
-                snmpSilentDrops, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpSilentDrops')
+                debug.logger & debug.flagApp and debug.logger(
+                    'processPdu: stateReference %s, statusInformation %s' % (stateReference, sys.exc_info()[1]))
+                snmpSilentDrops, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB',
+                                                                                                         'snmpSilentDrops')
                 snmpSilentDrops.syntax += 1
 
         elif PDU.tagSet in rfc3411.unconfirmedClassPDUs:
@@ -85,7 +90,9 @@ class NotificationReceiver:
         else:
             raise error.ProtocolError('Unexpected PDU class %s' % PDU.tagSet)
 
-        debug.logger & debug.flagApp and debug.logger('processPdu: stateReference %s, user cbFun %s, cbCtx %s, varBinds %s' % (stateReference, self.__cbFun, self.__cbCtx, varBinds))
+        debug.logger & debug.flagApp and debug.logger(
+            'processPdu: stateReference %s, user cbFun %s, cbCtx %s, varBinds %s' % (
+                stateReference, self.__cbFun, self.__cbCtx, varBinds))
 
         if self.__cbFunVer:
             self.__cbFun(snmpEngine, stateReference, contextEngineId,
diff --git a/pysnmp/entity/rfc3413/oneliner/cmdgen.py b/pysnmp/entity/rfc3413/oneliner/cmdgen.py
index 61bfbbbc..411fc40c 100644
--- a/pysnmp/entity/rfc3413/oneliner/cmdgen.py
+++ b/pysnmp/entity/rfc3413/oneliner/cmdgen.py
@@ -18,6 +18,7 @@ __all__ = ['AsynCommandGenerator', 'CommandGenerator', 'MibVariable']
 
 MibVariable = ObjectIdentity
 
+
 class AsynCommandGenerator:
     _null = univ.Null('')
 
@@ -26,7 +27,7 @@ class AsynCommandGenerator:
 
     def __init__(self, snmpEngine=None):
         if snmpEngine is None:
-            self.snmpEngine = snmpEngine = SnmpEngine()
+            self.snmpEngine = SnmpEngine()
         else:
             self.snmpEngine = snmpEngine
 
@@ -95,7 +96,6 @@ class AsynCommandGenerator:
         if contextName is null and authData.contextName:
             contextName = authData.contextName
 
-
         return setCmd(
             self.snmpEngine, authData, transportTarget,
             ContextData(contextEngineId, contextName), *varBinds,
@@ -159,8 +159,10 @@ class AsynCommandGenerator:
 
     asyncBulkCmd = bulkCmd
 
+
 class CommandGenerator:
     _null = univ.Null('')
+
     def __init__(self, snmpEngine=None, asynCmdGen=None):
         # compatibility attributes
         self.snmpEngine = snmpEngine or SnmpEngine()
@@ -172,8 +174,8 @@ class CommandGenerator:
             kwargs['lookupValues'] = False
         errorIndication, errorStatus, errorIndex, varBinds = None, 0, 0, []
         for errorIndication, \
-                errorStatus, errorIndex, \
-                varBinds \
+            errorStatus, errorIndex, \
+            varBinds \
                 in sync.getCmd(self.snmpEngine, authData, transportTarget,
                                ContextData(kwargs.get('contextEngineId'),
                                            kwargs.get('contextName', null)),
@@ -189,8 +191,8 @@ class CommandGenerator:
             kwargs['lookupValues'] = False
         errorIndication, errorStatus, errorIndex, rspVarBinds = None, 0, 0, []
         for errorIndication, \
-                errorStatus, errorIndex, \
-                rspVarBinds \
+            errorStatus, errorIndex, \
+            rspVarBinds \
                 in sync.setCmd(self.snmpEngine, authData, transportTarget,
                                ContextData(kwargs.get('contextEngineId'),
                                            kwargs.get('contextName', null)),
@@ -210,8 +212,8 @@ class CommandGenerator:
         errorIndication, errorStatus, errorIndex = None, 0, 0
         varBindTable = []
         for errorIndication, \
-                errorStatus, errorIndex, \
-                varBinds \
+            errorStatus, errorIndex, \
+            varBinds \
                 in sync.nextCmd(self.snmpEngine, authData, transportTarget,
                                 ContextData(kwargs.get('contextEngineId'),
                                             kwargs.get('contextName', null)),
@@ -235,8 +237,8 @@ class CommandGenerator:
         errorIndication, errorStatus, errorIndex = None, 0, 0
         varBindTable = []
         for errorIndication, \
-                errorStatus, errorIndex, \
-                varBinds \
+            errorStatus, errorIndex, \
+            varBinds \
                 in sync.bulkCmd(self.snmpEngine, authData,
                                 transportTarget,
                                 ContextData(kwargs.get('contextEngineId'),
diff --git a/pysnmp/entity/rfc3413/oneliner/ntforg.py b/pysnmp/entity/rfc3413/oneliner/ntforg.py
index ddb7438f..2436b5ba 100644
--- a/pysnmp/entity/rfc3413/oneliner/ntforg.py
+++ b/pysnmp/entity/rfc3413/oneliner/ntforg.py
@@ -21,6 +21,7 @@ __all__ = ['AsynNotificationOriginator',
 
 MibVariable = ObjectIdentity
 
+
 class ErrorIndicationReturn:
     def __init__(self, *vars):
         self.__vars = vars
@@ -29,7 +30,7 @@ class ErrorIndicationReturn:
         return self.__vars[i]
 
     def __nonzero__(self):
-        return self.__vars[0] and 1 or 0
+        return bool(self)
 
     def __bool__(self):
         return bool(self.__vars[0])
@@ -37,9 +38,11 @@ class ErrorIndicationReturn:
     def __str__(self):
         return str(self.__vars[0])
 
+
 class AsynNotificationOriginator:
     vbProcessor = NotificationOriginatorVarBinds()
     lcd = NotificationOriginatorLcdConfigurator()
+
     def __init__(self, snmpEngine=None, snmpContext=None):
         if snmpEngine is None:
             self.snmpEngine = snmpEngine = SnmpEngine()
@@ -133,8 +136,10 @@ class AsynNotificationOriginator:
 
     asyncSendNotification = sendNotification
 
+
 class NotificationOriginator:
     vbProcessor = NotificationOriginatorVarBinds()
+
     def __init__(self, snmpEngine=None, snmpContext=None, asynNtfOrg=None):
         # compatibility attributes
         self.snmpEngine = snmpEngine or SnmpEngine()
@@ -162,15 +167,15 @@ class NotificationOriginator:
         for errorIndication, \
             errorStatus, errorIndex, \
             rspVarBinds \
-            in sync.sendNotification(self.snmpEngine, authData,
-                                     transportTarget,
-                                     ContextData(
-                                         kwargs.get('contextEngineId'),
-                                         kwargs.get('contextName', null)
-                                     ),
-                                     notifyType,
-                                     notificationType.addVarBinds(*varBinds),
-                                     **kwargs):
+                in sync.sendNotification(self.snmpEngine, authData,
+                                         transportTarget,
+                                         ContextData(
+                                             kwargs.get('contextEngineId'),
+                                             kwargs.get('contextName', null)
+                                         ),
+                                         notifyType,
+                                         notificationType.addVarBinds(*varBinds),
+                                         **kwargs):
             if notifyType == 'inform':
                 return errorIndication, errorStatus, errorIndex, rspVarBinds
             else:
diff --git a/pysnmp/hlapi/__init__.py b/pysnmp/hlapi/__init__.py
index 44b7bb79..4680bd85 100644
--- a/pysnmp/hlapi/__init__.py
+++ b/pysnmp/hlapi/__init__.py
@@ -1,3 +1,9 @@
+#
+# This file is part of pysnmp software.
+#
+# Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
+# License: http://pysnmp.sf.net/license.html
+#
 from pysnmp.proto.rfc1902 import *
 from pysnmp.smi.rfc1902 import *
 from pysnmp.hlapi.auth import *
diff --git a/pysnmp/hlapi/asyncio/__init__.py b/pysnmp/hlapi/asyncio/__init__.py
index 9ec0fdfc..371931eb 100644
--- a/pysnmp/hlapi/asyncio/__init__.py
+++ b/pysnmp/hlapi/asyncio/__init__.py
@@ -1,3 +1,9 @@
+#
+# This file is part of pysnmp software.
+#
+# Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
+# License: http://pysnmp.sf.net/license.html
+#
 from pysnmp.proto.rfc1902 import *
 from pysnmp.smi.rfc1902 import *
 from pysnmp.entity.engine import *
diff --git a/pysnmp/hlapi/asyncio/cmdgen.py b/pysnmp/hlapi/asyncio/cmdgen.py
index bd82e611..d9a8d4d6 100644
--- a/pysnmp/hlapi/asyncio/cmdgen.py
+++ b/pysnmp/hlapi/asyncio/cmdgen.py
@@ -38,6 +38,7 @@ from pysnmp.hlapi.lcd import *
 from pysnmp.hlapi.varbinds import *
 from pysnmp.hlapi.asyncio.transport import *
 from pysnmp.entity.rfc3413 import cmdgen
+
 try:
     import asyncio
 except ImportError:
@@ -50,6 +51,7 @@ lcd = CommandGeneratorLcdConfigurator()
 
 isEndOfMib = lambda x: not cmdgen.getNextVarBinds(x)[1]
 
+
 @asyncio.coroutine
 def getCmd(snmpEngine, authData, transportTarget, contextData,
            *varBinds, **options):
@@ -125,6 +127,7 @@ def getCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle,
                 errorIndication, errorStatus, errorIndex,
                 varBinds, cbCtx):
@@ -147,6 +150,7 @@ def getCmd(snmpEngine, authData, transportTarget, contextData,
     )
     return future
 
+
 @asyncio.coroutine
 def setCmd(snmpEngine, authData, transportTarget, contextData,
            *varBinds, **options):
@@ -222,6 +226,7 @@ def setCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle,
                 errorIndication, errorStatus, errorIndex,
                 varBinds, cbCtx):
@@ -244,6 +249,7 @@ def setCmd(snmpEngine, authData, transportTarget, contextData,
     )
     return future
 
+
 @asyncio.coroutine
 def nextCmd(snmpEngine, authData, transportTarget, contextData,
             *varBinds, **options):
@@ -323,6 +329,7 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle,
                 errorIndication, errorStatus, errorIndex,
                 varBindTable, cbCtx):
@@ -330,7 +337,8 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
         if future.cancelled():
             return
         future.set_result(
-            (errorIndication, errorStatus, errorIndex, [vbProcessor.unmakeVarBinds(snmpEngine, varBindTableRow, lookupMib) for varBindTableRow in varBindTable])
+            (errorIndication, errorStatus, errorIndex,
+             [vbProcessor.unmakeVarBinds(snmpEngine, varBindTableRow, lookupMib) for varBindTableRow in varBindTable])
         )
 
     addrName, paramsName = lcd.configure(snmpEngine, authData, transportTarget)
@@ -345,6 +353,7 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
     )
     return future
 
+
 @asyncio.coroutine
 def bulkCmd(snmpEngine, authData, transportTarget, contextData,
             nonRepeaters, maxRepetitions, *varBinds, **options):
@@ -435,6 +444,7 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle,
                 errorIndication, errorStatus, errorIndex,
                 varBindTable, cbCtx):
@@ -442,7 +452,8 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
         if future.cancelled():
             return
         future.set_result(
-            (errorIndication, errorStatus, errorIndex, [vbProcessor.unmakeVarBinds(snmpEngine, varBindTableRow, lookupMib) for varBindTableRow in varBindTable])
+            (errorIndication, errorStatus, errorIndex,
+             [vbProcessor.unmakeVarBinds(snmpEngine, varBindTableRow, lookupMib) for varBindTableRow in varBindTable])
         )
 
     addrName, paramsName = lcd.configure(snmpEngine, authData, transportTarget)
diff --git a/pysnmp/hlapi/asyncio/ntforg.py b/pysnmp/hlapi/asyncio/ntforg.py
index cd0394a2..13ec63bd 100644
--- a/pysnmp/hlapi/asyncio/ntforg.py
+++ b/pysnmp/hlapi/asyncio/ntforg.py
@@ -15,6 +15,7 @@ from pysnmp.hlapi.lcd import *
 from pysnmp.hlapi.varbinds import *
 from pysnmp.hlapi.asyncio.transport import *
 from pysnmp.entity.rfc3413 import ntforg
+
 try:
     import asyncio
 except ImportError:
@@ -25,6 +26,7 @@ __all__ = ['sendNotification']
 vbProcessor = NotificationOriginatorVarBinds()
 lcd = NotificationOriginatorLcdConfigurator()
 
+
 @asyncio.coroutine
 def sendNotification(snmpEngine, authData, transportTarget, contextData,
                      notifyType, varBinds, **options):
@@ -115,6 +117,7 @@ def sendNotification(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle,
                 errorIndication, errorStatus, errorIndex,
                 varBinds, cbCtx):
diff --git a/pysnmp/hlapi/asyncio/transport.py b/pysnmp/hlapi/asyncio/transport.py
index b066b7ff..39a8edc4 100644
--- a/pysnmp/hlapi/asyncio/transport.py
+++ b/pysnmp/hlapi/asyncio/transport.py
@@ -4,13 +4,15 @@
 # Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
 # License: http://pysnmp.sf.net/license.html
 #
-import socket, sys
+import socket
+import sys
 from pysnmp.carrier.asyncio.dgram import udp, udp6
 from pysnmp.hlapi.transport import AbstractTransportTarget
 from pysnmp.error import PySnmpError
 
 __all__ = ['Udp6TransportTarget', 'UdpTransportTarget']
 
+
 class UdpTransportTarget(AbstractTransportTarget):
     """Creates UDP/IPv4 configuration entry and initialize socket API if needed.
 
@@ -47,6 +49,7 @@ class UdpTransportTarget(AbstractTransportTarget):
     """
     transportDomain = udp.domainName
     protoTransport = udp.UdpAsyncioTransport
+
     def _resolveAddr(self, transportAddr):
         try:
             return socket.getaddrinfo(transportAddr[0],
@@ -55,7 +58,9 @@ class UdpTransportTarget(AbstractTransportTarget):
                                       socket.SOCK_DGRAM,
                                       socket.IPPROTO_UDP)[0][4][:2]
         except socket.gaierror:
-            raise PySnmpError('Bad IPv4/UDP transport address %s: %s' % ('@'.join([str(x) for x in transportAddr]), sys.exc_info()[1]))
+            raise PySnmpError('Bad IPv4/UDP transport address %s: %s' % (
+                '@'.join([str(x) for x in transportAddr]), sys.exc_info()[1]))
+
 
 class Udp6TransportTarget(AbstractTransportTarget):
     """Creates UDP/IPv6 configuration entry and initialize socket API if needed.
@@ -105,6 +110,7 @@ class Udp6TransportTarget(AbstractTransportTarget):
     """
     transportDomain = udp6.domainName
     protoTransport = udp6.Udp6AsyncioTransport
+
     def _resolveAddr(self, transportAddr):
         try:
             return socket.getaddrinfo(transportAddr[0],
@@ -113,4 +119,5 @@ class Udp6TransportTarget(AbstractTransportTarget):
                                       socket.SOCK_DGRAM,
                                       socket.IPPROTO_UDP)[0][4][:2]
         except socket.gaierror:
-            raise PySnmpError('Bad IPv6/UDP transport address %s: %s' % ('@'.join([str(x) for x in transportAddr]), sys.exc_info()[1]))
+            raise PySnmpError('Bad IPv6/UDP transport address %s: %s' % (
+                '@'.join([str(x) for x in transportAddr]), sys.exc_info()[1]))
diff --git a/pysnmp/hlapi/asyncore/__init__.py b/pysnmp/hlapi/asyncore/__init__.py
index a6d2ecef..c1840741 100644
--- a/pysnmp/hlapi/asyncore/__init__.py
+++ b/pysnmp/hlapi/asyncore/__init__.py
@@ -1,3 +1,9 @@
+#
+# This file is part of pysnmp software.
+#
+# Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
+# License: http://pysnmp.sf.net/license.html
+#
 from pysnmp.proto.rfc1902 import *
 from pysnmp.smi.rfc1902 import *
 from pysnmp.hlapi.auth import *
diff --git a/pysnmp/hlapi/asyncore/cmdgen.py b/pysnmp/hlapi/asyncore/cmdgen.py
index 83f9efa8..776824d9 100644
--- a/pysnmp/hlapi/asyncore/cmdgen.py
+++ b/pysnmp/hlapi/asyncore/cmdgen.py
@@ -19,6 +19,7 @@ lcd = CommandGeneratorLcdConfigurator()
 
 isEndOfMib = lambda x: not cmdgen.getNextVarBinds(x)[1]
 
+
 def getCmd(snmpEngine, authData, transportTarget, contextData,
            *varBinds, **options):
     """Performs SNMP GET query.
@@ -108,6 +109,7 @@ def getCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle,
                 errorIndication, errorStatus, errorIndex,
                 varBinds, cbCtx):
@@ -129,6 +131,7 @@ def getCmd(snmpEngine, authData, transportTarget, contextData,
          options.get('cbFun'), options.get('cbCtx'))
     )
 
+
 def setCmd(snmpEngine, authData, transportTarget, contextData,
            *varBinds, **options):
     """Performs SNMP SET query.
@@ -218,6 +221,7 @@ def setCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle,
                 errorIndication, errorStatus, errorIndex,
                 varBinds, cbCtx):
@@ -237,6 +241,7 @@ def setCmd(snmpEngine, authData, transportTarget, contextData,
                   options.get('cbFun'), options.get('cbCtx'))
     )
 
+
 def nextCmd(snmpEngine, authData, transportTarget, contextData,
             *varBinds, **options):
     """Performs SNMP GETNEXT query.
@@ -328,12 +333,14 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle, errorIndication,
                 errorStatus, errorIndex, varBindTable, cbCtx):
         lookupMib, cbFun, cbCtx = cbCtx
         return cbFun(snmpEngine, sendRequestHandle, errorIndication,
                      errorStatus, errorIndex,
-                     [vbProcessor.unmakeVarBinds(snmpEngine, varBindTableRow, lookupMib) for varBindTableRow in varBindTable],
+                     [vbProcessor.unmakeVarBinds(snmpEngine, varBindTableRow, lookupMib) for varBindTableRow in
+                      varBindTable],
                      cbCtx)
 
     addrName, paramsName = lcd.configure(snmpEngine, authData, transportTarget)
@@ -345,6 +352,7 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
                   options.get('cbFun'), options.get('cbCtx'))
     )
 
+
 def bulkCmd(snmpEngine, authData, transportTarget, contextData,
             nonRepeaters, maxRepetitions, *varBinds, **options):
     """Performs SNMP GETBULK query.
@@ -447,12 +455,15 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
     def __cbFun(snmpEngine, sendRequestHandle,
                 errorIndication, errorStatus, errorIndex,
                 varBindTable, cbCtx):
         lookupMib, cbFun, cbCtx = cbCtx
         return cbFun(snmpEngine, sendRequestHandle, errorIndication,
-                     errorStatus, errorIndex, [vbProcessor.unmakeVarBinds(snmpEngine, varBindTableRow, lookupMib) for varBindTableRow in varBindTable], cbCtx)
+                     errorStatus, errorIndex,
+                     [vbProcessor.unmakeVarBinds(snmpEngine, varBindTableRow, lookupMib) for varBindTableRow in
+                      varBindTable], cbCtx)
 
     addrName, paramsName = lcd.configure(snmpEngine, authData, transportTarget)
     return cmdgen.BulkCommandGenerator().sendVarBinds(
diff --git a/pysnmp/hlapi/asyncore/ntforg.py b/pysnmp/hlapi/asyncore/ntforg.py
index abd173c6..03636bfa 100644
--- a/pysnmp/hlapi/asyncore/ntforg.py
+++ b/pysnmp/hlapi/asyncore/ntforg.py
@@ -17,6 +17,7 @@ __all__ = ['sendNotification']
 vbProcessor = NotificationOriginatorVarBinds()
 lcd = NotificationOriginatorLcdConfigurator()
 
+
 def sendNotification(snmpEngine, authData, transportTarget, contextData,
                      notifyType, varBinds, cbFun=None, cbCtx=None,
                      lookupMib=False):
@@ -46,7 +47,7 @@ def sendNotification(snmpEngine, authData, transportTarget, contextData,
         Indicates type of notification to be sent. Recognized literal
         values are *trap* or *inform*.
 
-    varBinds: tuple
+    varBinds : tuple
         Single :py:class:`~pysnmp.smi.rfc1902.NotificationType` class
         instance representing a minimum sequence of MIB variables
         required for particular notification type. Alternatively,
@@ -54,15 +55,6 @@ def sendNotification(snmpEngine, authData, transportTarget, contextData,
         objects could be passed instead. In the latter case it is up to
         the user to ensure proper Notification PDU contents.
 
-    cbInfo : tuple
-
-        * `cbFun` - user-supplied callable that is invoked to pass
-          SNMP response to *INFORM* notification or error to user at
-          a later point of time. The `cbFun` callable is never invoked
-          for *TRAP* notifications.
-        * `cbCtx` - user-supplied object passing additional parameters
-          to/from `cbFun`. Default is `None`.
-
     Other Parameters
     ----------------
     cbFun : callable
@@ -125,6 +117,8 @@ def sendNotification(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
+    # noinspection PyShadowingNames
     def __cbFun(snmpEngine, sendRequestHandle, errorIndication,
                 errorStatus, errorIndex, varBinds, cbCtx):
         lookupMib, cbFun, cbCtx = cbCtx
diff --git a/pysnmp/hlapi/asyncore/sync/__init__.py b/pysnmp/hlapi/asyncore/sync/__init__.py
index e2848cc1..54db456c 100644
--- a/pysnmp/hlapi/asyncore/sync/__init__.py
+++ b/pysnmp/hlapi/asyncore/sync/__init__.py
@@ -1,3 +1,9 @@
+#
+# This file is part of pysnmp software.
+#
+# Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
+# License: http://pysnmp.sf.net/license.html
+#
 from pysnmp.proto.rfc1902 import *
 from pysnmp.smi.rfc1902 import *
 from pysnmp.hlapi.auth import *
diff --git a/pysnmp/hlapi/asyncore/sync/cmdgen.py b/pysnmp/hlapi/asyncore/sync/cmdgen.py
index 7d891439..6d6bd233 100644
--- a/pysnmp/hlapi/asyncore/sync/cmdgen.py
+++ b/pysnmp/hlapi/asyncore/sync/cmdgen.py
@@ -16,9 +16,11 @@ __all__ = ['getCmd', 'nextCmd', 'setCmd', 'bulkCmd']
 if version_info[:2] < (2, 6):
     __all__.append('next')
 
+    # noinspection PyShadowingBuiltins
     def next(iter):
         return iter.next()
 
+
 def getCmd(snmpEngine, authData, transportTarget, contextData,
            *varBinds, **options):
     """Creates a generator to perform one or more SNMP GET queries.
@@ -89,6 +91,8 @@ def getCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBinds, cbCtx):
@@ -121,6 +125,7 @@ def getCmd(snmpEngine, authData, transportTarget, contextData,
         if not varBinds:
             break
 
+
 def setCmd(snmpEngine, authData, transportTarget, contextData,
            *varBinds, **options):
     """Creates a generator to perform one or more SNMP SET queries.
@@ -192,6 +197,8 @@ def setCmd(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBinds, cbCtx):
@@ -224,6 +231,7 @@ def setCmd(snmpEngine, authData, transportTarget, contextData,
         if not varBinds:
             break
 
+
 def nextCmd(snmpEngine, authData, transportTarget, contextData,
             *varBinds, **options):
     """Creates a generator to perform one or more SNMP GETNEXT queries.
@@ -316,6 +324,8 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
     >>> g.send( [ ObjectType(ObjectIdentity('IF-MIB', 'ifInOctets')) ] )
     (None, 0, 0, [(ObjectName('1.3.6.1.2.1.2.2.1.10.1'), Counter32(284817787))])
     """
+
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBindTable, cbCtx):
@@ -351,11 +361,11 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
             errorIndex = cbCtx['errorIndex']
 
             if ignoreNonIncreasingOid and errorIndication and \
-                   isinstance(errorIndication, errind.OidNotIncreasing):
+                    isinstance(errorIndication, errind.OidNotIncreasing):
                 errorIndication = None
 
             if errorIndication:
-                yield errorIndication, errorStatus, errorIndex, varBinds
+                yield (errorIndication, errorStatus, errorIndex, varBinds)
                 return
             elif errorStatus:
                 if errorStatus == 2:
@@ -363,7 +373,7 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
                     # from SNMPv1 Agent through internal pysnmp proxy.
                     errorStatus = errorStatus.clone(0)
                     errorIndex = errorIndex.clone(0)
-                yield errorIndication, errorStatus, errorIndex, varBinds
+                yield (errorIndication, errorStatus, errorIndex, varBinds)
                 return
             else:
                 varBinds = cbCtx['varBindTable'] and cbCtx['varBindTable'][0]
@@ -381,17 +391,17 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
             errorIndication = errorStatus = errorIndex = None
             varBinds = []
 
-        initialVarBinds = (yield errorIndication, errorStatus,\
-                                 errorIndex, varBinds)
+        initialVarBinds = (yield errorIndication, errorStatus, errorIndex, varBinds)
 
         if initialVarBinds:
             varBinds = initialVarBinds
             initialVars = [x[0] for x in vbProcessor.makeVarBinds(snmpEngine, varBinds)]
 
         if maxRows and totalRows >= maxRows or \
-                 maxCalls and totalCalls >= maxCalls:
+                maxCalls and totalCalls >= maxCalls:
             return
 
+
 def bulkCmd(snmpEngine, authData, transportTarget, contextData,
             nonRepeaters, maxRepetitions, *varBinds, **options):
     """Creates a generator to perform one or more SNMP GETBULK queries.
@@ -499,6 +509,8 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
     >>> g.send( [ ObjectType(ObjectIdentity('IF-MIB', 'ifInOctets')) ] )
     (None, 0, 0, [(ObjectName('1.3.6.1.2.1.2.2.1.10.1'), Counter32(284817787))])
     """
+
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBindTable, cbCtx):
@@ -524,7 +536,7 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
 
     while not stopFlag:
         if maxRows and totalRows < maxRows:
-            maxRepetitions = min(maxRepetitions, maxRows-totalRows)
+            maxRepetitions = min(maxRepetitions, maxRows - totalRows)
 
         cmdgen.bulkCmd(snmpEngine, authData, transportTarget, contextData,
                        nonRepeaters, maxRepetitions,
@@ -544,8 +556,8 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
             errorIndication = None
 
         if errorIndication:
-            yield errorIndication, errorStatus, errorIndex, \
-                    varBindTable and varBindTable[0] or []
+            yield (errorIndication, errorStatus, errorIndex,
+                   varBindTable and varBindTable[0] or [])
             if errorIndication != errind.requestTimedOut:
                 return
         elif errorStatus:
@@ -554,14 +566,13 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
                 # from SNMPv1 Agent through internal pysnmp proxy.
                 errorStatus = errorStatus.clone(0)
                 errorIndex = errorIndex.clone(0)
-            yield errorIndication, errorStatus, errorIndex, \
-                    varBindTable and varBindTable[0] or []
+            yield (errorIndication, errorStatus, errorIndex, varBindTable and varBindTable[0] or [])
             return
         else:
             for i in range(len(varBindTable)):
                 stopFlag = True
                 if len(varBindTable[i]) != len(initialVars):
-                    varBindTable = i and varBindTable[:i-1] or []
+                    varBindTable = i and varBindTable[:i - 1] or []
                     break
                 for j in range(len(varBindTable[i])):
                     name, val = varBindTable[i][j]
@@ -572,11 +583,11 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
                     if isinstance(val, Null):
                         nullVarBinds[j] = True
                     elif not lexicographicMode and \
-                                not initialVars[j].isPrefixOf(name):
+                            not initialVars[j].isPrefixOf(name):
                         varBindTable[i][j] = name, endOfMibView
                         nullVarBinds[j] = True
                 if stopFlag:
-                    varBindTable = i and varBindTable[:i-1] or []
+                    varBindTable = i and varBindTable[:i - 1] or []
                     break
 
             totalRows += len(varBindTable)
@@ -584,15 +595,14 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
 
             if maxRows and totalRows >= maxRows:
                 if totalRows > maxRows:
-                    varBindTable = varBindTable[:-(totalRows-maxRows)]
+                    varBindTable = varBindTable[:-(totalRows - maxRows)]
                 stopFlag = True
 
             if maxCalls and totalCalls >= maxCalls:
                 stopFlag = True
 
             for varBinds in varBindTable:
-                initialVarBinds = (yield errorIndication, errorStatus,\
-                                         errorIndex, varBinds)
+                initialVarBinds = (yield errorIndication, errorStatus, errorIndex, varBinds)
 
                 if initialVarBinds:
                     varBinds = initialVarBinds
diff --git a/pysnmp/hlapi/asyncore/sync/compat/cmdgen.py b/pysnmp/hlapi/asyncore/sync/compat/cmdgen.py
index 1f6b1ece..13ad3bfa 100644
--- a/pysnmp/hlapi/asyncore/sync/compat/cmdgen.py
+++ b/pysnmp/hlapi/asyncore/sync/compat/cmdgen.py
@@ -14,12 +14,15 @@ from pyasn1.type.univ import Null
 
 __all__ = ['getCmd', 'nextCmd', 'setCmd', 'bulkCmd', 'next']
 
+
+# noinspection PyShadowingBuiltins
 def next(iter):
     return iter.next()
 
+
 def getCmd(snmpEngine, authData, transportTarget, contextData,
            *varBinds, **options):
-
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBinds, cbCtx):
@@ -48,9 +51,10 @@ def getCmd(snmpEngine, authData, transportTarget, contextData,
 
     yield errorIndication, errorStatus, errorIndex, varBinds
 
+
 def setCmd(snmpEngine, authData, transportTarget, contextData,
            *varBinds, **options):
-
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBinds, cbCtx):
@@ -69,16 +73,17 @@ def setCmd(snmpEngine, authData, transportTarget, contextData,
 
         snmpEngine.transportDispatcher.runDispatcher()
 
-        yield cbCtx['errorIndication'],  \
-              cbCtx['errorStatus'], cbCtx['errorIndex'], \
-              cbCtx['varBinds']
+        yield (cbCtx['errorIndication'],
+               cbCtx['errorStatus'], cbCtx['errorIndex'],
+               cbCtx['varBinds'])
 
         if cbCtx['errorIndication'] != errind.requestTimedOut:
             break
 
+
 def nextCmd(snmpEngine, authData, transportTarget, contextData,
             *varBinds, **options):
-
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBindTable, cbCtx):
@@ -113,7 +118,7 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
         errorIndex = cbCtx['errorIndex']
 
         if ignoreNonIncreasingOid and errorIndication and \
-               isinstance(errorIndication, errind.OidNotIncreasing):
+                isinstance(errorIndication, errind.OidNotIncreasing):
             errorIndication = None
 
         if errorIndication:
@@ -144,12 +149,13 @@ def nextCmd(snmpEngine, authData, transportTarget, contextData,
             yield errorIndication, errorStatus, errorIndex, varBinds
 
             if maxRows and totalRows >= maxRows or \
-                     maxCalls and totalCalls >= maxCalls:
+                    maxCalls and totalCalls >= maxCalls:
                 return
 
+
 def bulkCmd(snmpEngine, authData, transportTarget, contextData,
             nonRepeaters, maxRepetitions, *varBinds, **options):
-
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBindTable, cbCtx):
@@ -175,7 +181,7 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
 
     while not stopFlag:
         if maxRows and totalRows < maxRows:
-            maxRepetitions = min(maxRepetitions, maxRows-totalRows)
+            maxRepetitions = min(maxRepetitions, maxRows - totalRows)
 
         cmdgen.bulkCmd(snmpEngine, authData, transportTarget, contextData,
                        nonRepeaters, maxRepetitions,
@@ -195,8 +201,8 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
             errorIndication = None
 
         if errorIndication:
-            yield errorIndication, errorStatus, errorIndex, \
-                    varBindTable and varBindTable[0] or []
+            yield (errorIndication, errorStatus, errorIndex,
+                   varBindTable and varBindTable[0] or [])
             if errorIndication != errind.requestTimedOut:
                 return
         elif errorStatus:
@@ -205,14 +211,14 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
                 # from SNMPv1 Agent through internal pysnmp proxy.
                 errorStatus = errorStatus.clone(0)
                 errorIndex = errorIndex.clone(0)
-            yield errorIndication, errorStatus, errorIndex, \
-                    varBindTable and varBindTable[0] or []
+            yield (errorIndication, errorStatus, errorIndex,
+                   varBindTable and varBindTable[0] or [])
             return
         else:
             for i in range(len(varBindTable)):
                 stopFlag = True
                 if len(varBindTable[i]) != len(initialVars):
-                    varBindTable = i and varBindTable[:i-1] or []
+                    varBindTable = i and varBindTable[:i - 1] or []
                     break
                 for j in range(len(varBindTable[i])):
                     name, val = varBindTable[i][j]
@@ -223,11 +229,11 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
                     if isinstance(val, Null):
                         nullVarBinds[j] = True
                     elif not lexicographicMode and \
-                                not initialVars[j].isPrefixOf(name):
+                            not initialVars[j].isPrefixOf(name):
                         varBindTable[i][j] = name, endOfMibView
                         nullVarBinds[j] = True
                 if stopFlag:
-                    varBindTable = i and varBindTable[:i-1] or []
+                    varBindTable = i and varBindTable[:i - 1] or []
                     break
 
             totalRows += len(varBindTable)
@@ -235,7 +241,7 @@ def bulkCmd(snmpEngine, authData, transportTarget, contextData,
 
             if maxRows and totalRows >= maxRows:
                 if totalRows > maxRows:
-                    varBindTable = varBindTable[:-(totalRows-maxRows)]
+                    varBindTable = varBindTable[:-(totalRows - maxRows)]
                 stopFlag = True
 
             if maxCalls and totalCalls >= maxCalls:
diff --git a/pysnmp/hlapi/asyncore/sync/compat/ntforg.py b/pysnmp/hlapi/asyncore/sync/compat/ntforg.py
index 88b37041..01e3914a 100644
--- a/pysnmp/hlapi/asyncore/sync/compat/ntforg.py
+++ b/pysnmp/hlapi/asyncore/sync/compat/ntforg.py
@@ -10,16 +10,19 @@ from pysnmp.hlapi.asyncore import ntforg
 
 __all__ = ['sendNotification', 'next']
 
+
+# noinspection PyShadowingBuiltins
 def next(iter):
     return iter.next()
 
+
 #
 # Synchronous one-liner SNMP Notification Originator application
 #
 
 def sendNotification(snmpEngine, authData, transportTarget, contextData,
                      notifyType, varBinds, **options):
-
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBinds, cbCtx):
diff --git a/pysnmp/hlapi/asyncore/sync/ntforg.py b/pysnmp/hlapi/asyncore/sync/ntforg.py
index a4f22115..2f60d94a 100644
--- a/pysnmp/hlapi/asyncore/sync/ntforg.py
+++ b/pysnmp/hlapi/asyncore/sync/ntforg.py
@@ -12,9 +12,11 @@ __all__ = ['sendNotification']
 if version_info[:2] < (2, 6):
     __all__.append('next')
 
+    # noinspection PyShadowingBuiltins
     def next(iter):
         return iter.next()
 
+
 def sendNotification(snmpEngine, authData, transportTarget, contextData,
                      notifyType, varBinds, **options):
     """Creates a generator to send one or more SNMP notifications.
@@ -96,6 +98,8 @@ def sendNotification(snmpEngine, authData, transportTarget, contextData,
     >>>
 
     """
+
+    # noinspection PyShadowingNames
     def cbFun(snmpEngine, sendRequestHandle,
               errorIndication, errorStatus, errorIndex,
               varBinds, cbCtx):
diff --git a/pysnmp/hlapi/asyncore/transport.py b/pysnmp/hlapi/asyncore/transport.py
index ffa4b785..39450781 100644
--- a/pysnmp/hlapi/asyncore/transport.py
+++ b/pysnmp/hlapi/asyncore/transport.py
@@ -4,13 +4,15 @@
 # Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
 # License: http://pysnmp.sf.net/license.html
 #
-import socket, sys
+import socket
+import sys
 from pysnmp.carrier.asyncore.dgram import udp, udp6, unix
 from pysnmp.hlapi.transport import AbstractTransportTarget
 from pysnmp import error
 
 __all__ = ['UnixTransportTarget', 'Udp6TransportTarget', 'UdpTransportTarget']
 
+
 class UdpTransportTarget(AbstractTransportTarget):
     """Creates UDP/IPv4 configuration entry and initialize socket API if needed.
 
@@ -47,6 +49,7 @@ class UdpTransportTarget(AbstractTransportTarget):
     """
     transportDomain = udp.domainName
     protoTransport = udp.UdpSocketTransport
+
     def _resolveAddr(self, transportAddr):
         try:
             return socket.getaddrinfo(transportAddr[0],
@@ -55,7 +58,9 @@ class UdpTransportTarget(AbstractTransportTarget):
                                       socket.SOCK_DGRAM,
                                       socket.IPPROTO_UDP)[0][4][:2]
         except socket.gaierror:
-            raise error.PySnmpError('Bad IPv4/UDP transport address %s: %s' % ('@'.join([str(x) for x in transportAddr]), sys.exc_info()[1]))
+            raise error.PySnmpError('Bad IPv4/UDP transport address %s: %s' % (
+                '@'.join([str(x) for x in transportAddr]), sys.exc_info()[1]))
+
 
 class Udp6TransportTarget(AbstractTransportTarget):
     """Creates UDP/IPv6 configuration entry and initialize socket API if needed.
@@ -102,6 +107,7 @@ class Udp6TransportTarget(AbstractTransportTarget):
     """
     transportDomain = udp6.domainName
     protoTransport = udp6.Udp6SocketTransport
+
     def _resolveAddr(self, transportAddr):
         try:
             return socket.getaddrinfo(transportAddr[0],
@@ -110,7 +116,9 @@ class Udp6TransportTarget(AbstractTransportTarget):
                                       socket.SOCK_DGRAM,
                                       socket.IPPROTO_UDP)[0][4][:2]
         except socket.gaierror:
-            raise error.PySnmpError('Bad IPv6/UDP transport address %s: %s' % ('@'.join([str(x) for x in transportAddr]), sys.exc_info()[1]))
+            raise error.PySnmpError('Bad IPv6/UDP transport address %s: %s' % (
+                '@'.join([str(x) for x in transportAddr]), sys.exc_info()[1]))
+
 
 class UnixTransportTarget(AbstractTransportTarget):
     transportDomain = unix.domainName
diff --git a/pysnmp/hlapi/auth.py b/pysnmp/hlapi/auth.py
index 2af90cef..821c0c3a 100644
--- a/pysnmp/hlapi/auth.py
+++ b/pysnmp/hlapi/auth.py
@@ -15,6 +15,7 @@ __all__ = ['CommunityData', 'UsmUserData',
            'usmHMACSHAAuthProtocol', 'usmNoAuthProtocol',
            'usmNoPrivProtocol']
 
+
 class CommunityData:
     """Creates SNMP v1/v2c configuration entry.
 
@@ -59,11 +60,12 @@ class CommunityData:
     >>>
 
     """
-    mpModel = 1 # Default is SMIv2
+    mpModel = 1  # Default is SMIv2
     securityModel = mpModel + 1
     securityLevel = 'noAuthNoPriv'
     contextName = null
     tag = null
+
     def __init__(self, communityIndex, communityName=None, mpModel=None,
                  contextEngineId=None, contextName=None, tag=None,
                  securityName=None):
@@ -119,6 +121,7 @@ class CommunityData:
             securityName is None and self.securityName or securityName
         )
 
+
 #: No Authentication Protocol.
 usmNoAuthProtocol = config.usmNoAuthProtocol
 #: The HMAC-MD5-96 Digest Authentication Protocol (:RFC:`3414#section-6`)
@@ -139,6 +142,7 @@ usmAesCfb192Protocol = config.usmAesCfb192Protocol
 #: The CFB128-AES-256 Symmetric Encryption Protocol (`draft-blumenthal-aes-usm-04 <https://tools.ietf.org/html/draft-blumenthal-aes-usm-04#section-3>`_)
 usmAesCfb256Protocol = config.usmAesCfb256Protocol
 
+
 class UsmUserData:
     """Creates SNMP v3 User Security Model (USM) configuration entry.
 
@@ -208,6 +212,7 @@ class UsmUserData:
     securityModel = 3
     mpModel = 3
     contextName = null
+
     # the contextEngineId/contextName values stored here should
     # be used for USM configuration only, not for PDU contents
     def __init__(self, userName,
@@ -257,7 +262,7 @@ class UsmUserData:
         raise TypeError('%s is not hashable' % self.__class__.__name__)
 
     def __repr__(self):
-        return '%s(userName=%r, authKey=<AUTHKEY>, privKey=<PRIVKEY>, authProtocol=%r, privProtocol=%r, securityEngineId=%r, securityName=%r)'%(
+        return '%s(userName=%r, authKey=<AUTHKEY>, privKey=<PRIVKEY>, authProtocol=%r, privProtocol=%r, securityEngineId=%r, securityName=%r)' % (
             self.__class__.__name__,
             self.userName,
             self.authProtocol,
diff --git a/pysnmp/hlapi/context.py b/pysnmp/hlapi/context.py
index 14ceecda..363efeac 100644
--- a/pysnmp/hlapi/context.py
+++ b/pysnmp/hlapi/context.py
@@ -8,6 +8,7 @@ from pyasn1.compat.octets import null
 
 __all__ = ['ContextData']
 
+
 class ContextData:
     """Creates UDP/IPv6 configuration entry and initialize socket API if needed.
 
@@ -44,6 +45,7 @@ class ContextData:
     ContextData(contextEngineId=None, contextName='mycontext')
 
     """
+
     def __init__(self, contextEngineId=None, contextName=null):
         self.contextEngineId = contextEngineId
         self.contextName = contextName
diff --git a/pysnmp/hlapi/lcd.py b/pysnmp/hlapi/lcd.py
index 53a46edf..f96b695b 100644
--- a/pysnmp/hlapi/lcd.py
+++ b/pysnmp/hlapi/lcd.py
@@ -11,9 +11,11 @@ from pysnmp.hlapi.auth import *
 __all__ = ['CommandGeneratorLcdConfigurator',
            'NotificationOriginatorLcdConfigurator']
 
+
 class AbstractLcdConfigurator:
     nextID = nextid.Integer(0xffffffff)
     cacheKeys = []
+
     def _getCache(self, snmpEngine):
         cacheId = self.__class__.__name__
         cache = snmpEngine.getUserContext(cacheId)
@@ -22,15 +24,17 @@ class AbstractLcdConfigurator:
             snmpEngine.setUserContext(**{cacheId: cache})
         return cache
 
-    def configure(self, snmpEngine, authData, transportTarget):
+    def configure(self, snmpEngine, authData, transportTarget, *options):
         pass
 
     def unconfigure(self, snmpEngine, authData=None):
         pass
 
+
 class CommandGeneratorLcdConfigurator(AbstractLcdConfigurator):
     cacheKeys = ['auth', 'parm', 'tran', 'addr']
-    def configure(self, snmpEngine, authData, transportTarget):
+
+    def configure(self, snmpEngine, authData, transportTarget, *options):
         cache = self._getCache(snmpEngine)
         if isinstance(authData, CommunityData):
             if authData.communityIndex not in cache['auth']:
@@ -59,9 +63,9 @@ class CommandGeneratorLcdConfigurator(AbstractLcdConfigurator):
         else:
             raise error.PySnmpError('Unsupported authentication object')
 
-        paramsKey = authData.securityName, \
-                    authData.securityLevel, \
-                    authData.mpModel
+        paramsKey = (authData.securityName,
+                     authData.securityLevel,
+                     authData.mpModel)
         if paramsKey in cache['parm']:
             paramsName, useCount = cache['parm'][paramsKey]
             cache['parm'][paramsKey] = paramsName, useCount + 1
@@ -145,9 +149,9 @@ class CommandGeneratorLcdConfigurator(AbstractLcdConfigurator):
             else:
                 raise error.PySnmpError('Unsupported authentication object')
 
-            paramsKey = authDataX.securityName, \
-                        authDataX.securityLevel, \
-                        authDataX.mpModel
+            paramsKey = (authDataX.securityName,
+                         authDataX.securityLevel,
+                         authDataX.mpModel)
             if paramsKey in cache['parm']:
                 paramsName, useCount = cache['parm'][paramsKey]
                 useCount -= 1
@@ -186,11 +190,15 @@ class CommandGeneratorLcdConfigurator(AbstractLcdConfigurator):
 
         return addrNames, paramsNames
 
+
 class NotificationOriginatorLcdConfigurator(AbstractLcdConfigurator):
     cacheKeys = ['auth', 'name']
     _cmdGenLcdCfg = CommandGeneratorLcdConfigurator()
-    def configure(self, snmpEngine, authData, transportTarget, notifyType):
+
+    def configure(self, snmpEngine, authData, transportTarget, *options):
         cache = self._getCache(snmpEngine)
+        notifyType = options and options[0] or 'trap'
+        notifyName = None
 
         # Create matching transport tags if not given by user. Not good!
         if not transportTarget.tagList:
@@ -220,7 +228,7 @@ class NotificationOriginatorLcdConfigurator(AbstractLcdConfigurator):
                 )
                 cache['name'][notifyNameKey] = notifyName, paramsName, 1
         authDataKey = authData.securityName, authData.securityModel
-        if  authDataKey in cache['auth']:
+        if authDataKey in cache['auth']:
             authDataX, subTree, useCount = cache['auth'][authDataKey]
             cache['auth'][authDataKey] = authDataX, subTree, useCount + 1
         else:
diff --git a/pysnmp/hlapi/transport.py b/pysnmp/hlapi/transport.py
index 3a062816..45807f2e 100644
--- a/pysnmp/hlapi/transport.py
+++ b/pysnmp/hlapi/transport.py
@@ -10,15 +10,18 @@ from pysnmp import error
 
 __all__ = []
 
+
 class AbstractTransportTarget:
     transportDomain = None
     protoTransport = AbstractTransport
+
     def __init__(self, transportAddr, timeout=1, retries=5, tagList=null):
         self.transportAddr = self._resolveAddr(transportAddr)
         self.timeout = timeout
         self.retries = retries
         self.tagList = tagList
         self.iface = None
+        self.transport = None
 
     def __repr__(self):
         return '%s(%r, timeout=%r, retries=%r, tagList=%r)' % (
@@ -39,7 +42,8 @@ class AbstractTransportTarget:
 
     def verifyDispatcherCompatibility(self, snmpEngine):
         if not self.protoTransport.isCompatibleWithDispatcher(snmpEngine.transportDispatcher):
-            raise error.PySnmpError('Transport %r is not compatible with dispatcher %r' % (self.protoTransport, snmpEngine.transportDispatcher))
+            raise error.PySnmpError('Transport %r is not compatible with dispatcher %r' % (
+                self.protoTransport, snmpEngine.transportDispatcher))
 
     def _resolveAddr(self, transportAddr):
         raise NotImplementedError()
diff --git a/pysnmp/hlapi/varbinds.py b/pysnmp/hlapi/varbinds.py
index 9b52e4cc..b5617113 100644
--- a/pysnmp/hlapi/varbinds.py
+++ b/pysnmp/hlapi/varbinds.py
@@ -9,8 +9,10 @@ from pysnmp.smi.rfc1902 import *
 
 __all__ = ['CommandGeneratorVarBinds', 'NotificationOriginatorVarBinds']
 
+
 class AbstractVarBinds:
-    def getMibViewController(self, snmpEngine):
+    @staticmethod
+    def getMibViewController(snmpEngine):
         mibViewController = snmpEngine.getUserContext('mibViewController')
         if not mibViewController:
             mibViewController = view.MibViewController(
@@ -19,6 +21,7 @@ class AbstractVarBinds:
             snmpEngine.setUserContext(mibViewController=mibViewController)
         return mibViewController
 
+
 class CommandGeneratorVarBinds(AbstractVarBinds):
     def makeVarBinds(self, snmpEngine, varBinds):
         mibViewController = self.getMibViewController(snmpEngine)
@@ -44,6 +47,7 @@ class CommandGeneratorVarBinds(AbstractVarBinds):
 
         return varBinds
 
+
 class NotificationOriginatorVarBinds(AbstractVarBinds):
     def makeVarBinds(self, snmpEngine, varBinds):
         mibViewController = self.getMibViewController(snmpEngine)
@@ -65,4 +69,3 @@ class NotificationOriginatorVarBinds(AbstractVarBinds):
             mibViewController = self.getMibViewController(snmpEngine)
             varBinds = [ObjectType(ObjectIdentity(x[0]), x[1]).resolveWithMib(mibViewController) for x in varBinds]
         return varBinds
-
diff --git a/pysnmp/proto/acmod/rfc3415.py b/pysnmp/proto/acmod/rfc3415.py
index 917dc5d7..3c6be611 100644
--- a/pysnmp/proto/acmod/rfc3415.py
+++ b/pysnmp/proto/acmod/rfc3415.py
@@ -10,10 +10,12 @@ from pysnmp import debug
 
 __powOfTwoSeq = [128, 64, 32, 16, 8, 4, 2, 1]
 
+
 # 3.2
 class Vacm:
     """View-based Access Control Model"""
     accessModelID = 3
+
     def isAccessAllowed(self,
                         snmpEngine,
                         securityModel,
@@ -24,7 +26,9 @@ class Vacm:
                         variableName):
         mibInstrumController = snmpEngine.msgAndPduDsp.mibInstrumController
 
-        debug.logger & debug.flagACL and debug.logger('isAccessAllowed: securityModel %s, securityName %s, securityLevel %s, viewType %s, contextName %s for variableName %s' % (securityModel, securityName, securityLevel, viewType, contextName, variableName))
+        debug.logger & debug.flagACL and debug.logger(
+            'isAccessAllowed: securityModel %s, securityName %s, securityLevel %s, viewType %s, contextName %s for variableName %s' % (
+                securityModel, securityName, securityLevel, viewType, contextName, variableName))
 
         # 3.2.1
         vacmContextEntry, = mibInstrumController.mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB', 'vacmContextEntry')
@@ -37,7 +41,8 @@ class Vacm:
             raise error.StatusInformation(errorIndication=errind.noSuchContext)
 
         # 3.2.2
-        vacmSecurityToGroupEntry, = mibInstrumController.mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB', 'vacmSecurityToGroupEntry')
+        vacmSecurityToGroupEntry, = mibInstrumController.mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB',
+                                                                                  'vacmSecurityToGroupEntry')
         tblIdx = vacmSecurityToGroupEntry.getInstIdFromIndices(
             securityModel, securityName
         )
@@ -77,7 +82,8 @@ class Vacm:
         # XXX split onto object & instance ?
 
         # 3.2.5a
-        vacmViewTreeFamilyEntry, = mibInstrumController.mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB', 'vacmViewTreeFamilyEntry')
+        vacmViewTreeFamilyEntry, = mibInstrumController.mibBuilder.importSymbols('SNMP-VIEW-BASED-ACM-MIB',
+                                                                                 'vacmViewTreeFamilyEntry')
         tblIdx = vacmViewTreeFamilyEntry.getInstIdFromIndices(viewName)
 
         # Walk over entries
@@ -101,18 +107,18 @@ class Vacm:
             if vacmViewTreeFamilyMask.syntax:
                 mask = []
                 for c in vacmViewTreeFamilyMask.syntax.asNumbers():
-                    mask = mask + [b&c for b in __powOfTwoSeq]
-                m = len(mask)-1
-                idx = l-1
+                    mask = mask + [b & c for b in __powOfTwoSeq]
+                m = len(mask) - 1
+                idx = l - 1
                 while idx:
                     if idx > m or mask[idx] and \
-                       vacmViewTreeFamilySubtree.syntax[idx] != variableName[idx]:
+                            vacmViewTreeFamilySubtree.syntax[idx] != variableName[idx]:
                         break
-                    idx = idx - 1
+                    idx -= 1
                 if idx:
-                    continue # no match
-            else: # no mask
+                    continue  # no match
+            else:  # no mask
                 if vacmViewTreeFamilySubtree.syntax != variableName[:l]:
-                    continue # no match
+                    continue  # no match
             # 3.2.5c
             return error.StatusInformation(errorIndication=errind.accessAllowed)
diff --git a/pysnmp/proto/api/__init__.py b/pysnmp/proto/api/__init__.py
index 47782bf2..c904896b 100644
--- a/pysnmp/proto/api/__init__.py
+++ b/pysnmp/proto/api/__init__.py
@@ -1,3 +1,9 @@
+#
+# This file is part of pysnmp software.
+#
+# Copyright (c) 2005-2016, Ilya Etingof <ilya@glas.net>
+# License: http://pysnmp.sf.net/license.html
+#
 from pysnmp.proto.api import v1, v2c, verdec
 
 # Protocol versions
diff --git a/pysnmp/proto/api/v1.py b/pysnmp/proto/api/v1.py
index b6a8dabf..9bab214e 100644
--- a/pysnmp/proto/api/v1.py
+++ b/pysnmp/proto/api/v1.py
@@ -31,25 +31,32 @@ SetRequestPDU = rfc1157.SetRequestPDU
 TrapPDU = rfc1157.TrapPDU
 Message = rfc1157.Message
 
+
 class VarBindAPI:
-    def setOIDVal(self, varBind, oidVal):
+    @staticmethod
+    def setOIDVal(varBind, oidVal):
         (oid, val) = oidVal
         varBind.setComponentByPosition(0, oid)
         if val is None:
             val = null
-        varBind.setComponentByPosition(1).getComponentByPosition(1).setComponentByType(val.getTagSet(), val, 1, verifyConstraints=False)
+        varBind.setComponentByPosition(1).getComponentByPosition(1).setComponentByType(val.getTagSet(), val, 1,
+                                                                                       verifyConstraints=False)
         return varBind
 
-    def getOIDVal(self, varBind):
+    @staticmethod
+    def getOIDVal(varBind):
         return varBind[0], varBind[1].getComponent(1)
 
+
 apiVarBind = VarBindAPI()
 
 getNextRequestID = nextid.Integer(0xffffff)
 
+
 class PDUAPI:
-    _errorStatus = rfc1157._errorStatus.clone(0)
+    _errorStatus = rfc1157.errorStatus.clone(0)
     _errorIndex = Integer(0)
+
     def setDefaults(self, pdu):
         pdu.setComponentByPosition(
             0, getNextRequestID(), verifyConstraints=False
@@ -62,19 +69,24 @@ class PDUAPI:
         )
         pdu.setComponentByPosition(3)
 
-    def getRequestID(self, pdu):
+    @staticmethod
+    def getRequestID(pdu):
         return pdu.getComponentByPosition(0)
 
-    def setRequestID(self, pdu, value):
+    @staticmethod
+    def setRequestID(pdu, value):
         pdu.setComponentByPosition(0, value)
 
-    def getErrorStatus(self, pdu):
+    @staticmethod
+    def getErrorStatus(pdu):
         return pdu.getComponentByPosition(1)
 
-    def setErrorStatus(self, pdu, value):
+    @staticmethod
+    def setErrorStatus(pdu, value):
         pdu.setComponentByPosition(1, value)
 
-    def getErrorIndex(self, pdu, muteErrors=False):
+    @staticmethod
+    def getErrorIndex(pdu, muteErrors=False):
         errorIndex = pdu.getComponentByPosition(2)
         if errorIndex > len(pdu[3]):
             if muteErrors:
@@ -84,7 +96,8 @@ class PDUAPI:
             )
         return errorIndex
 
-    def setErrorIndex(self, pdu, value):
+    @staticmethod
+    def setErrorIndex(pdu, value):
         pdu.setComponentByPosition(2, value)
 
     def setEndOfMibError(self, pdu, errorIndex):
@@ -94,19 +107,23 @@ class PDUAPI:
     def setNoSuchInstanceError(self, pdu, errorIndex):
         self.setEndOfMibError(pdu, errorIndex)
 
-    def getVarBindList(self, pdu):
+    @staticmethod
+    def getVarBindList(pdu):
         return pdu.getComponentByPosition(3)
 
-    def setVarBindList(self, pdu, varBindList):
-        varBindList = pdu.setComponentByPosition(3, varBindList)
+    @staticmethod
+    def setVarBindList(pdu, varBindList):
+        pdu.setComponentByPosition(3, varBindList)
 
-    def getVarBinds(self, pdu):
+    @staticmethod
+    def getVarBinds(pdu):
         varBinds = []
         for varBind in pdu.getComponentByPosition(3):
             varBinds.append(apiVarBind.getOIDVal(varBind))
         return varBinds
 
-    def setVarBinds(self, pdu, varBinds):
+    @staticmethod
+    def setVarBinds(pdu, varBinds):
         varBindList = pdu.setComponentByPosition(3).getComponentByPosition(3)
         varBindList.clear()
         idx = 0
@@ -135,22 +152,25 @@ class PDUAPI:
         else:
             return [apiPDU.getVarBinds(rspPDU)]
 
+
 apiPDU = PDUAPI()
 
+
 class TrapPDUAPI:
     _networkAddress = None
     _entOid = ObjectIdentifier((1, 3, 6, 1, 4, 1, 20408))
-    _genericTrap = rfc1157._genericTrap.clone('coldStart')
+    _genericTrap = rfc1157.genericTrap.clone('coldStart')
     _zeroInt = univ.Integer(0)
     _zeroTime = TimeTicks(0)
+
     def setDefaults(self, pdu):
         if self._networkAddress is None:
             try:
                 import socket
                 agentAddress = IpAddress(socket.gethostbyname(socket.gethostname()))
-            except:
+            except Exception:
                 agentAddress = IpAddress('0.0.0.0')
-        self._networkAddress = NetworkAddress().setComponentByPosition(0, agentAddress)
+            self._networkAddress = NetworkAddress().setComponentByPosition(0, agentAddress)
         pdu.setComponentByPosition(0, self._entOid, verifyConstraints=False)
         pdu.setComponentByPosition(1, self._networkAddress, verifyConstraints=False)
         pdu.setComponentByPosition(2, self._genericTrap, verifyConstraints=False)
@@ -158,49 +178,63 @@ class TrapPDUAPI:
         pdu.setComponentByPosition(4, self._zeroTime, verifyConstraints=False)
         pdu.setComponentByPosition(5)
 
-    def getEnterprise(self, pdu):
+    @staticmethod
+    def getEnterprise(pdu):
         return pdu.getComponentByPosition(0)
 
-    def setEnterprise(self, pdu, value):
+    @staticmethod
+    def setEnterprise(pdu, value):
         pdu.setComponentByPosition(0, value)
 
-    def getAgentAddr(self, pdu):
+    @staticmethod
+    def getAgentAddr(pdu):
         return pdu.getComponentByPosition(1).getComponentByPosition(0)
 
-    def setAgentAddr(self, pdu, value):
+    @staticmethod
+    def setAgentAddr(pdu, value):
         pdu.setComponentByPosition(1).getComponentByPosition(1).setComponentByPosition(0, value)
 
-    def getGenericTrap(self, pdu):
+    @staticmethod
+    def getGenericTrap(pdu):
         return pdu.getComponentByPosition(2)
 
-    def setGenericTrap(self, pdu, value):
+    @staticmethod
+    def setGenericTrap(pdu, value):
         pdu.setComponentByPosition(2, value)
 
-    def getSpecificTrap(self, pdu):
+    @staticmethod
+    def getSpecificTrap(pdu):
         return pdu.getComponentByPosition(3)
 
-    def setSpecificTrap(self, pdu, value):
+    @staticmethod
+    def setSpecificTrap(pdu, value):
         pdu.setComponentByPosition(3, value)
 
-    def getTimeStamp(self, pdu):
+    @staticmethod
+    def getTimeStamp(pdu):
         return pdu.getComponentByPosition(4)
 
-    def setTimeStamp(self, pdu, value):
+    @staticmethod
+    def setTimeStamp(pdu, value):
         pdu.setComponentByPosition(4, value)
 
-    def getVarBindList(self, pdu):
+    @staticmethod
+    def getVarBindList(pdu):
         return pdu.getComponentByPosition(5)
 
-    def setVarBindList(self, pdu, varBindList):
-        varBindList = pdu.setComponentByPosition(5, varBindList)
+    @staticmethod
+    def setVarBindList(pdu, varBindList):
+        pdu.setComponentByPosition(5, varBindList)
 
-    def getVarBinds(self, pdu):
+    @staticmethod
+    def getVarBinds(pdu):
         varBinds = []
         for varBind in pdu.getComponentByPosition(5):
             varBinds.append(apiVarBind.getOIDVal(varBind))
         return varBinds
 
-    def setVarBinds(self, pdu, varBinds):
+    @staticmethod
+    def setVarBinds(pdu, varBinds):
         varBindList = pdu.setComponentByPosition(5).getComponentByPosition(5)
         varBindList.clear()
         idx = 0
@@ -211,36 +245,46 @@ class TrapPDUAPI:
                 varBindList.setComponentByPosition(idx)
                 apiVarBind.setOIDVal(
                     varBindList.getComponentByPosition(idx), varBind
-                    )
-            idx = idx + 1
+                )
+            idx += 1
+
 
 apiTrapPDU = TrapPDUAPI()
 
+
 class MessageAPI:
-    _version = rfc1157._version.clone(0)
+    _version = rfc1157.version.clone(0)
     _community = univ.OctetString('public')
+
     def setDefaults(self, msg):
         msg.setComponentByPosition(0, self._version, verifyConstraints=False)
         msg.setComponentByPosition(1, self._community, verifyConstraints=False)
         return msg
 
-    def getVersion(self, msg):
+    @staticmethod
+    def getVersion(msg):
         return msg.getComponentByPosition(0)
 
-    def setVersion(self, msg, value):
+    @staticmethod
+    def setVersion(msg, value):
         msg.setComponentByPosition(0, value)
 
-    def getCommunity(self, msg):
+    @staticmethod
+    def getCommunity(msg):
         return msg.getComponentByPosition(1)
 
-    def setCommunity(self, msg, value):
+    @staticmethod
+    def setCommunity(msg, value):
         msg.setComponentByPosition(1, value)
 
-    def getPDU(self, msg):
+    @staticmethod
+    def getPDU(msg):
         return msg.getComponentByPosition(2).getComponent()
 
-    def setPDU(self, msg, value):
-        msg.setComponentByPosition(2).getComponentByPosition(2).setComponentByType(value.getTagSet(), value, 1, verifyConstraints=False)
+    @staticmethod
+    def setPDU(msg, value):
+        msg.setComponentByPosition(2).getComponentByPosition(2).setComponentByType(value.getTagSet(), value, 1,
+                                                                                   verifyConstraints=False)
 
     def getResponse(self, reqMsg):
         rspMsg = Message()
@@ -250,4 +294,5 @@ class MessageAPI:
         self.setPDU(rspMsg, apiPDU.getResponse(self.getPDU(reqMsg)))
         return rspMsg
 
+
 apiMessage = MessageAPI()
diff --git a/pysnmp/proto/api/v2c.py b/pysnmp/proto/api/v2c.py
index 96dcfc67..fa8f6799 100644
--- a/pysnmp/proto/api/v2c.py
+++ b/pysnmp/proto/api/v2c.py
@@ -46,8 +46,9 @@ getNextRequestID = v1.getNextRequestID
 
 apiVarBind = v1.apiVarBind
 
+
 class PDUAPI(v1.PDUAPI):
-    _errorStatus = rfc1905._errorStatus.clone(0)
+    _errorStatus = rfc1905.errorStatus.clone(0)
     _errorIndex = univ.Integer(0).subtype(subtypeSpec=constraint.ValueRangeConstraint(0, rfc1905.max_bindings))
 
     def getResponse(self, reqPDU):
@@ -61,21 +62,24 @@ class PDUAPI(v1.PDUAPI):
 
     def setEndOfMibError(self, pdu, errorIndex):
         varBindList = self.getVarBindList(pdu)
-        varBindList[errorIndex-1].setComponentByPosition(
+        varBindList[errorIndex - 1].setComponentByPosition(
             1, rfc1905.endOfMibView, verifyConstraints=False
         )
 
     def setNoSuchInstanceError(self, pdu, errorIndex):
         varBindList = self.getVarBindList(pdu)
-        varBindList[errorIndex-1].setComponentByPosition(
+        varBindList[errorIndex - 1].setComponentByPosition(
             1, rfc1905.noSuchInstance, verifyConstraints=False
         )
 
+
 apiPDU = PDUAPI()
 
+
 class BulkPDUAPI(PDUAPI):
-    _nonRepeaters = rfc1905._nonRepeaters.clone(0)
-    _maxRepetitions = rfc1905._maxRepetitions.clone(10)
+    _nonRepeaters = rfc1905.nonRepeaters.clone(0)
+    _maxRepetitions = rfc1905.maxRepetitions.clone(10)
+
     def setDefaults(self, pdu):
         PDUAPI.setDefaults(self, pdu)
         pdu.setComponentByPosition(
@@ -89,34 +93,37 @@ class BulkPDUAPI(PDUAPI):
         )
         pdu.setComponentByPosition(3)
 
-    def getNonRepeaters(self, pdu):
+    @staticmethod
+    def getNonRepeaters(pdu):
         return pdu.getComponentByPosition(1)
 
-    def setNonRepeaters(self, pdu, value):
+    @staticmethod
+    def setNonRepeaters(pdu, value):
         pdu.setComponentByPosition(1, value)
 
-    def getMaxRepetitions(self, pdu):
+    @staticmethod
+    def getMaxRepetitions(pdu):
         return pdu.getComponentByPosition(2)
 
-    def setMaxRepetitions(self, pdu, value):
+    @staticmethod
+    def setMaxRepetitions(pdu, value):
         pdu.setComponentByPosition(2, value)
 
     def getVarBindTable(self, reqPDU, rspPDU):
         nonRepeaters = self.getNonRepeaters(reqPDU)
-        maxRepetitions = self.getMaxRepetitions(reqPDU)
 
         reqVarBinds = self.getVarBinds(reqPDU)
 
         N = min(int(nonRepeaters), len(reqVarBinds))
-        R = max(len(reqVarBinds)-N, 0)
+        R = max(len(reqVarBinds) - N, 0)
 
         rspVarBinds = self.getVarBinds(rspPDU)
 
         varBindTable = []
 
         if R:
-            for i in range(0, len(rspVarBinds)-N, R):
-                varBindRow = rspVarBinds[:N] + rspVarBinds[N+i:N+R+i]
+            for i in range(0, len(rspVarBinds) - N, R):
+                varBindRow = rspVarBinds[:N] + rspVarBinds[N + i:N + R + i]
                 # ignore stray OIDs / non-rectangular table
                 if len(varBindRow) == N + R:
                     varBindTable.append(varBindRow)
@@ -125,8 +132,10 @@ class BulkPDUAPI(PDUAPI):
 
         return varBindTable
 
+
 apiBulkPDU = BulkPDUAPI()
 
+
 class TrapPDUAPI(v1.PDUAPI):
     sysUpTime = (1, 3, 6, 1, 2, 1, 1, 3, 0)
     snmpTrapAddress = (1, 3, 6, 1, 6, 3, 18, 1, 3, 0)
@@ -135,6 +144,7 @@ class TrapPDUAPI(v1.PDUAPI):
     snmpTrapEnterprise = (1, 3, 6, 1, 6, 3, 1, 1, 4, 3, 0)
     _zeroTime = TimeTicks(0)
     _genTrap = ObjectIdentifier((1, 3, 6, 1, 6, 3, 1, 1, 5, 1))
+
     def setDefaults(self, pdu):
         v1.PDUAPI.setDefaults(self, pdu)
         varBinds = [(self.sysUpTime, self._zeroTime),
@@ -142,10 +152,13 @@ class TrapPDUAPI(v1.PDUAPI):
                     (self.snmpTrapOID, self._genTrap)]
         self.setVarBinds(pdu, varBinds)
 
+
 apiTrapPDU = TrapPDUAPI()
 
+
 class MessageAPI(v1.MessageAPI):
-    _version = rfc1901._version.clone(1)
+    _version = rfc1901.version.clone(1)
+
     def setDefaults(self, msg):
         msg.setComponentByPosition(0, self._version, verifyConstraints=False)
         msg.setComponentByPosition(1, self._community, verifyConstraints=False)
@@ -159,4 +172,5 @@ class MessageAPI(v1.MessageAPI):
         self.setPDU(rspMsg, apiPDU.getResponse(self.getPDU(reqMsg)))
         return rspMsg
 
+
 apiMessage = MessageAPI()
diff --git a/pysnmp/proto/api/verdec.py b/pysnmp/proto/api/verdec.py
index 627d857f..15aa363a 100644
--- a/pysnmp/proto/api/verdec.py
+++ b/pysnmp/proto/api/verdec.py
@@ -9,6 +9,7 @@ from pyasn1.codec.ber import decoder, eoo
 from pyasn1.error import PyAsn1Error
 from pysnmp.proto.error import ProtocolError
 
+
 def decodeMessageVersion(wholeMsg):
     try:
         seq, wholeMsg = decoder.decode(
diff --git a/pysnmp/proto/mpmod/base.py b/pysnmp/proto/mpmod/base.py
index c24fccaf..b9d5820a 100644
--- a/pysnmp/proto/mpmod/base.py
+++ b/pysnmp/proto/mpmod/base.py
@@ -7,8 +7,10 @@
 from pysnmp.proto.mpmod import cache
 from pysnmp.proto import error
 
+
 class AbstractMessageProcessingModel:
     snmpMsgSpec = NotImplementedError
+
     def __init__(self):
         self._snmpMsgSpec = self.snmpMsgSpec()  # local copy
         self._cache = cache.Cache()
@@ -35,7 +37,7 @@ class AbstractMessageProcessingModel:
         try:
             self._cache.popBySendPduHandle(sendPduHandle)
         except error.ProtocolError:
-            pass # XXX maybe these should all follow some scheme?
+            pass  # XXX maybe these should all follow some scheme?
 
     def receiveTimerTick(self, snmpEngine, timeNow):
         self._cache.expireCaches()
diff --git a/pysnmp/proto/mpmod/cache.py b/pysnmp/proto/mpmod/cache.py
index 94dc19ef..43027d5c 100644
--- a/pysnmp/proto/mpmod/cache.py
+++ b/pysnmp/proto/mpmod/cache.py
@@ -7,9 +7,11 @@
 from pysnmp.proto import error
 from pysnmp import nextid
 
+
 class Cache:
     __stateReference = nextid.Integer(0xffffff)
     __msgID = nextid.Integer(0xffffff)
+
     def __init__(self):
         self.__msgIdIndex = {}
         self.__stateReferenceIndex = {}
@@ -26,7 +28,7 @@ class Cache:
     def pushByStateRef(self, stateReference, **msgInfo):
         if stateReference in self.__stateReferenceIndex:
             raise error.ProtocolError('Cache dup for stateReference=%s at %s' % (stateReference, self))
-        expireAt = self.__expirationTimer+600
+        expireAt = self.__expirationTimer + 600
         self.__stateReferenceIndex[stateReference] = msgInfo, expireAt
 
         # Schedule to expire
@@ -56,7 +58,7 @@ class Cache:
             raise error.ProtocolError(
                 'Cache dup for msgId=%s at %s' % (msgId, self)
             )
-        expireAt = self.__expirationTimer+600
+        expireAt = self.__expirationTimer + 600
         self.__msgIdIndex[msgId] = msgInfo, expireAt
 
         self.__sendPduHandleIdx[msgInfo['sendPduHandle']] = msgId
diff --git a/pysnmp/proto/mpmod/rfc2576.py b/pysnmp/proto/mpmod/rfc2576.py
index 48ec7eb0..fb4341cf 100644
--- a/pysnmp/proto/mpmod/rfc2576.py
+++ b/pysnmp/proto/mpmod/rfc2576.py
@@ -14,20 +14,24 @@ from pysnmp.proto import rfc3411, errind, error
 from pysnmp.proto.api import v1, v2c
 from pysnmp import debug
 
+
 # Since I have not found a detailed reference to v1MP/v2cMP
 # inner workings, the following has been patterned from v3MP. Most
 # references here goes to RFC3412.
 
 class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
-    messageProcessingModelID = univ.Integer(0) # SNMPv1
+    messageProcessingModelID = univ.Integer(0)  # SNMPv1
     snmpMsgSpec = v1.Message
+
     # rfc3412: 7.1
     def prepareOutgoingMessage(self, snmpEngine, transportDomain,
                                transportAddress, messageProcessingModel,
                                securityModel, securityName, securityLevel,
                                contextEngineId, contextName, pduVersion,
                                pdu, expectResponse, sendPduHandle):
-        snmpEngineId, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+        mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+        snmpEngineId, = mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
         snmpEngineId = snmpEngineId.syntax
 
         # rfc3412: 7.1.1b
@@ -36,7 +40,8 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
             pdu.setComponentByPosition(1)
             msgID = self._cache.newMsgID()
             reqID = pdu.getComponentByPosition(0)
-            debug.logger & debug.flagMP and debug.logger('prepareOutgoingMessage: PDU request-id %s replaced with unique ID %s' % (reqID, msgID))
+            debug.logger & debug.flagMP and debug.logger(
+                'prepareOutgoingMessage: PDU request-id %s replaced with unique ID %s' % (reqID, msgID))
 
         # rfc3412: 7.1.4
         # Since there's no SNMP engine identification in v1/2c,
@@ -48,7 +53,8 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
         if not contextName:
             contextName = null
 
-        debug.logger & debug.flagMP and debug.logger('prepareOutgoingMessage: using contextEngineId %r contextName %r' % (contextEngineId, contextName))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareOutgoingMessage: using contextEngineId %r contextName %r' % (contextEngineId, contextName))
 
         # rfc3412: 7.1.6
         scopedPDU = (contextEngineId, contextName, pdu)
@@ -73,22 +79,25 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
 
         # rfc3412: 7.1.9.a & rfc2576: 5.2.1 --> no-op
 
-        snmpEngineMaxMessageSize, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
+        snmpEngineMaxMessageSize, = mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB',
+                                                             'snmpEngineMaxMessageSize')
 
         # fix unique request-id right prior PDU serialization
         if pdu.tagSet in rfc3411.confirmedClassPDUs:
+            # noinspection PyUnboundLocalVariable
             pdu.setComponentByPosition(0, msgID)
 
         # rfc3412: 7.1.9.b
         (securityParameters,
          wholeMsg) = smHandler.generateRequestMsg(
-             snmpEngine, self.messageProcessingModelID, globalData,
-             snmpEngineMaxMessageSize.syntax, securityModel,
-             snmpEngineId, securityName, securityLevel, scopedPDU
-         )
+            snmpEngine, self.messageProcessingModelID, globalData,
+            snmpEngineMaxMessageSize.syntax, securityModel,
+            snmpEngineId, securityName, securityLevel, scopedPDU
+        )
 
         # return original request-id right after PDU serialization
         if pdu.tagSet in rfc3411.confirmedClassPDUs:
+            # noinspection PyUnboundLocalVariable
             pdu.setComponentByPosition(0, reqID)
 
         # rfc3412: 7.1.9.c
@@ -131,7 +140,9 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
                                contextEngineId, contextName, pduVersion,
                                pdu, maxSizeResponseScopedPDU, stateReference,
                                statusInformation):
-        snmpEngineId, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+        mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
+        snmpEngineId, = mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
         snmpEngineId = snmpEngineId.syntax
 
         # rfc3412: 7.1.2.b
@@ -151,7 +162,9 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
         transportDomain = cachedParams['transportDomain']
         transportAddress = cachedParams['transportAddress']
 
-        debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: cache read msgID %s transportDomain %s transportAddress %s by stateReference %s' % (msgID, transportDomain, transportAddress, stateReference))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareResponseMessage: cache read msgID %s transportDomain %s transportAddress %s by stateReference %s' % (
+                msgID, transportDomain, transportAddress, stateReference))
 
         # rfc3412: 7.1.3
         if statusInformation:
@@ -173,7 +186,8 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
         # rfc3412: 7.1.6
         scopedPDU = (contextEngineId, contextName, pdu)
 
-        debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: using contextEngineId %r contextName %r' % (contextEngineId, contextName))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareResponseMessage: using contextEngineId %r contextName %r' % (contextEngineId, contextName))
 
         msg = self._snmpMsgSpec
         msg.setComponentByPosition(0, messageProcessingModel)
@@ -231,13 +245,14 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
 
     def prepareDataElements(self, snmpEngine, transportDomain,
                             transportAddress, wholeMsg):
+        mibBuilder = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder
+
         # rfc3412: 7.2.2
         try:
-            msg, restOfwholeMsg = decoder.decode(wholeMsg,
-                                                 asn1Spec=self._snmpMsgSpec)
+            msg, restOfWholeMsg = decoder.decode(wholeMsg, asn1Spec=self._snmpMsgSpec)
         except PyAsn1Error:
             debug.logger & debug.flagMP and debug.logger('prepareDataElements: %s' % (sys.exc_info()[1],))
-            snmpInASNParseErrs, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpInASNParseErrs')
+            snmpInASNParseErrs, = mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpInASNParseErrs')
             snmpInASNParseErrs.syntax += 1
             raise error.StatusInformation(errorIndication=errind.parseError)
 
@@ -247,14 +262,13 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
             raise error.StatusInformation(errorIndication=errind.parseError)
 
         # rfc3412: 7.2.3
-        msgVersion = messageProcessingModel = msg.getComponentByPosition(0)
+        msgVersion = msg.getComponentByPosition(0)
 
         # rfc2576: 5.2.1
-        snmpEngineMaxMessageSize, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
+        snmpEngineMaxMessageSize, = mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
         communityName = msg.getComponentByPosition(1)
         # transportDomain identifies local enpoint
-        securityParameters = (communityName,
-                              (transportDomain, transportAddress))
+        securityParameters = (communityName, (transportDomain, transportAddress))
         messageProcessingModel = int(msg.getComponentByPosition(0))
         securityModel = messageProcessingModel + 1
         securityLevel = 1
@@ -270,14 +284,15 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
             )
 
         # rfc3412: 7.2.6
-        (securityEngineId, securityName, scopedPDU, maxSizeResponseScopedPDU,
-         securityStateReference) = smHandler.processIncomingMsg(
-             snmpEngine, messageProcessingModel,
-             snmpEngineMaxMessageSize.syntax, securityParameters,
-             securityModel, securityLevel, wholeMsg, msg
-         )
+        (securityEngineId, securityName, scopedPDU,
+         maxSizeResponseScopedPDU, securityStateReference) = smHandler.processIncomingMsg(
+            snmpEngine, messageProcessingModel,
+            snmpEngineMaxMessageSize.syntax, securityParameters,
+            securityModel, securityLevel, wholeMsg, msg
+        )
 
-        debug.logger & debug.flagMP and debug.logger('prepareDataElements: SM returned securityEngineId %r securityName %r' % (securityEngineId, securityName))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareDataElements: SM returned securityEngineId %r securityName %r' % (securityEngineId, securityName))
 
         # rfc3412: 7.2.6a --> noop
 
@@ -305,7 +320,9 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
             # recover original PDU request-id to return to app
             pdu.setComponentByPosition(0, cachedReqParams['reqID'])
 
-            debug.logger & debug.flagMP and debug.logger('prepareDataElements: unique PDU request-id %s replaced with original ID %s' % (msgID, cachedReqParams['reqID']))
+            debug.logger & debug.flagMP and debug.logger(
+                'prepareDataElements: unique PDU request-id %s replaced with original ID %s' % (
+                    msgID, cachedReqParams['reqID']))
 
             # 7.2.10b
             sendPduHandle = cachedReqParams['sendPduHandle']
@@ -321,11 +338,12 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
         if pduType in rfc3411.responseClassPDUs:
             # rfc3412: 7.2.12a -> noop
             # rfc3412: 7.2.12b
+            # noinspection PyUnboundLocalVariable
             if securityModel != cachedReqParams['securityModel'] or \
-                   securityName != cachedReqParams['securityName'] or \
-                   securityLevel != cachedReqParams['securityLevel'] or \
-                   contextEngineId != cachedReqParams['contextEngineId'] or \
-                   contextName != cachedReqParams['contextName']:
+                    securityName != cachedReqParams['securityName'] or \
+                    securityLevel != cachedReqParams['securityLevel'] or \
+                    contextEngineId != cachedReqParams['contextEngineId'] or \
+                    contextName != cachedReqParams['contextName']:
                 smHandler.releaseStateInformation(securityStateReference)
                 raise error.StatusInformation(errorIndication=errind.dataMismatch)
 
@@ -364,10 +382,11 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
             reqID = pdu.getComponentByPosition(0)
             msgID = self._cache.newMsgID()
             pdu.setComponentByPosition(0, msgID)
-            debug.logger & debug.flagMP and debug.logger('prepareDataElements: received PDU request-id %s replaced with unique ID %s' % (reqID, msgID))
+            debug.logger & debug.flagMP and debug.logger(
+                'prepareDataElements: received PDU request-id %s replaced with unique ID %s' % (reqID, msgID))
 
             # rfc3412: 7.2.13a
-            snmpEngineId, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+            snmpEngineId, = mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
             if securityEngineId != snmpEngineId.syntax:
                 smHandler.releaseStateInformation(securityStateReference)
                 raise error.StatusInformation(
@@ -405,7 +424,8 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
                 snmpEngine, 'rfc2576.prepareDataElements:confirmed'
             )
 
-            debug.logger & debug.flagMP and debug.logger('prepareDataElements: cached by new stateReference %s' % stateReference)
+            debug.logger & debug.flagMP and debug.logger(
+                'prepareDataElements: cached by new stateReference %s' % stateReference)
 
             # rfc3412: 7.2.13c
             return (messageProcessingModel, securityModel, securityName,
@@ -448,6 +468,7 @@ class SnmpV1MessageProcessingModel(AbstractMessageProcessingModel):
         smHandler.releaseStateInformation(securityStateReference)
         raise error.StatusInformation(errorIndication=errind.unsupportedPDUtype)
 
+
 class SnmpV2cMessageProcessingModel(SnmpV1MessageProcessingModel):
-    messageProcessingModelID = univ.Integer(1) # SNMPv2c
+    messageProcessingModelID = univ.Integer(1)  # SNMPv2c
     snmpMsgSpec = v2c.Message
diff --git a/pysnmp/proto/mpmod/rfc3412.py b/pysnmp/proto/mpmod/rfc3412.py
index 103719bf..90f3dd9b 100644
--- a/pysnmp/proto/mpmod/rfc3412.py
+++ b/pysnmp/proto/mpmod/rfc3412.py
@@ -15,6 +15,7 @@ from pysnmp import debug
 # API to rfc1905 protocol objects
 pMod = api.protoModules[api.protoVersion2c]
 
+
 # SNMPv3 message format
 
 class ScopedPDU(univ.Sequence):
@@ -24,28 +25,36 @@ class ScopedPDU(univ.Sequence):
         namedtype.NamedType('data', rfc1905.PDUs())
     )
 
+
 class ScopedPduData(univ.Choice):
     componentType = namedtype.NamedTypes(
         namedtype.NamedType('plaintext', ScopedPDU()),
         namedtype.NamedType('encryptedPDU', univ.OctetString()),
     )
 
+
 class HeaderData(univ.Sequence):
     componentType = namedtype.NamedTypes(
-        namedtype.NamedType('msgID', univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, 2147483647))),
-        namedtype.NamedType('msgMaxSize', univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(484, 2147483647))),
+        namedtype.NamedType('msgID',
+                            univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, 2147483647))),
+        namedtype.NamedType('msgMaxSize',
+                            univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(484, 2147483647))),
         namedtype.NamedType('msgFlags', univ.OctetString().subtype(subtypeSpec=constraint.ValueSizeConstraint(1, 1))),
-        namedtype.NamedType('msgSecurityModel', univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(1, 2147483647)))
+        namedtype.NamedType('msgSecurityModel',
+                            univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(1, 2147483647)))
     )
 
+
 class SNMPv3Message(univ.Sequence):
     componentType = namedtype.NamedTypes(
-        namedtype.NamedType('msgVersion', univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, 2147483647))),
+        namedtype.NamedType('msgVersion',
+                            univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, 2147483647))),
         namedtype.NamedType('msgGlobalData', HeaderData()),
         namedtype.NamedType('msgSecurityParameters', univ.OctetString()),
         namedtype.NamedType('msgData', ScopedPduData())
     )
 
+
 # XXX move somewhere?
 _snmpErrors = {(1, 3, 6, 1, 6, 3, 15, 1, 1, 1, 0): 'unsupportedSecLevel',
                (1, 3, 6, 1, 6, 3, 15, 1, 1, 2, 0): 'notInTimeWindow',
@@ -54,8 +63,9 @@ _snmpErrors = {(1, 3, 6, 1, 6, 3, 15, 1, 1, 1, 0): 'unsupportedSecLevel',
                (1, 3, 6, 1, 6, 3, 15, 1, 1, 5, 0): 'wrongDigest',
                (1, 3, 6, 1, 6, 3, 15, 1, 1, 6, 0): 'decryptionError'}
 
+
 class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
-    messageProcessingModelID = univ.Integer(3) # SNMPv3
+    messageProcessingModelID = univ.Integer(3)  # SNMPv3
     snmpMsgSpec = SNMPv3Message
     _emptyStr = univ.OctetString('')
     _msgFlags = {0: univ.OctetString('\x00'),
@@ -64,6 +74,7 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
                  4: univ.OctetString('\x04'),
                  5: univ.OctetString('\x05'),
                  7: univ.OctetString('\x07')}
+
     def __init__(self):
         AbstractMessageProcessingModel.__init__(self)
         self.__scopedPDU = ScopedPDU()
@@ -74,9 +85,9 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
     def getPeerEngineInfo(self, transportDomain, transportAddress):
         k = transportDomain, transportAddress
         if k in self.__engineIdCache:
-            return self.__engineIdCache[k]['securityEngineId'], \
-                   self.__engineIdCache[k]['contextEngineId'], \
-                   self.__engineIdCache[k]['contextName']
+            return (self.__engineIdCache[k]['securityEngineId'],
+                    self.__engineIdCache[k]['contextEngineId'],
+                    self.__engineIdCache[k]['contextName'])
         else:
             return None, None, None
 
@@ -86,7 +97,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
                                securityModel, securityName, securityLevel,
                                contextEngineId, contextName, pduVersion,
                                pdu, expectResponse, sendPduHandle):
-        snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+        snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB',
+                                                                                              'snmpEngineID')
         snmpEngineID = snmpEngineID.syntax
 
         # 7.1.1b
@@ -100,7 +112,9 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         else:
             peerSnmpEngineData = None
 
-        debug.logger & debug.flagMP and debug.logger('prepareOutgoingMessage: peer SNMP engine data %s for transport %s, address %s' % (peerSnmpEngineData, transportDomain, transportAddress))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareOutgoingMessage: peer SNMP engine data %s for transport %s, address %s' % (
+                peerSnmpEngineData, transportDomain, transportAddress))
 
         # 7.1.4
         if contextEngineId is None:
@@ -117,7 +131,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         if not contextName:
             contextName = self._emptyStr
 
-        debug.logger & debug.flagMP and debug.logger('prepareOutgoingMessage: using contextEngineId %r, contextName %r' % (contextEngineId, contextName))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareOutgoingMessage: using contextEngineId %r, contextName %r' % (contextEngineId, contextName))
 
         # 7.1.6
         scopedPDU = self.__scopedPDU
@@ -140,7 +155,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         # 7.1.7b
         headerData.setComponentByPosition(0, msgID, verifyConstraints=False)
 
-        snmpEngineMaxMessageSize, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
+        snmpEngineMaxMessageSize, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+            '__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
 
         # 7.1.7c
         # XXX need to coerce MIB value as it has incompatible constraints set
@@ -153,16 +169,16 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         if securityLevel == 1:
             pass
         elif securityLevel == 2:
-            msgFlags = msgFlags | 0x01
+            msgFlags |= 0x01
         elif securityLevel == 3:
-            msgFlags = msgFlags | 0x03
+            msgFlags |= 0x03
         else:
             raise error.ProtocolError(
                 'Unknown securityLevel %s' % securityLevel
             )
 
         if pdu.tagSet in rfc3411.confirmedClassPDUs:
-            msgFlags = msgFlags | 0x04
+            msgFlags |= 0x04
 
         headerData.setComponentByPosition(
             2, self._msgFlags[msgFlags], verifyConstraints=False
@@ -212,15 +228,17 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
             else:
                 securityEngineId = peerSnmpEngineData['securityEngineId']
 
-        debug.logger & debug.flagMP and debug.logger('prepareOutgoingMessage: securityModel %r, securityEngineId %r, securityName %r, securityLevel %r' % (securityModel, securityEngineId, securityName, securityLevel))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareOutgoingMessage: securityModel %r, securityEngineId %r, securityName %r, securityLevel %r' % (
+                securityModel, securityEngineId, securityName, securityLevel))
 
         # 7.1.9.b
         (securityParameters,
          wholeMsg) = smHandler.generateRequestMsg(
-             snmpEngine, self.messageProcessingModelID, msg,
-             snmpEngineMaxMessageSize.syntax, securityModel,
-             securityEngineId, securityName, securityLevel, scopedPDU
-         )
+            snmpEngine, self.messageProcessingModelID, msg,
+            snmpEngineMaxMessageSize.syntax, securityModel,
+            securityEngineId, securityName, securityLevel, scopedPDU
+        )
 
         # Message size constraint verification
         if len(wholeMsg) > snmpEngineMaxMessageSize.syntax:
@@ -262,7 +280,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
                                contextEngineId, contextName, pduVersion,
                                pdu, maxSizeResponseScopedPDU, stateReference,
                                statusInformation):
-        snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+        snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB',
+                                                                                              'snmpEngineID')
         snmpEngineID = snmpEngineID.syntax
 
         # 7.1.2.b
@@ -279,21 +298,21 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         transportDomain = cachedParams['transportDomain']
         transportAddress = cachedParams['transportAddress']
 
-        debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: stateReference %s' % (stateReference))
+        debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: stateReference %s' % stateReference)
 
         # 7.1.3
         if statusInformation is not None and 'oid' in statusInformation:
             # 7.1.3a
-            if pdu is not None:
+            if pdu is None:
+                pduType = None
+            else:
                 requestID = pdu.getComponentByPosition(0)
                 pduType = pdu.tagSet
-            else:
-                pduType = None
 
             # 7.1.3b
             if pdu is None and not reportableFlag or \
-                   pduType is not None and \
-                   pduType not in rfc3411.confirmedClassPDUs:
+                    pduType is not None and \
+                    pduType not in rfc3411.confirmedClassPDUs:
                 raise error.StatusInformation(
                     errorIndication=errind.loopTerminated
                 )
@@ -306,6 +325,7 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
             if pdu is None:
                 pMod.apiPDU.setRequestID(reportPDU, 0)
             else:
+                # noinspection PyUnboundLocalVariable
                 pMod.apiPDU.setRequestID(reportPDU, requestID)
 
             # 7.1.3d.1
@@ -329,7 +349,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
             # 7.1.3e
             pdu = reportPDU
 
-            debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: prepare report PDU for statusInformation %s' % statusInformation)
+            debug.logger & debug.flagMP and debug.logger(
+                'prepareResponseMessage: prepare report PDU for statusInformation %s' % statusInformation)
         # 7.1.4
         if not contextEngineId:
             contextEngineId = snmpEngineID  # XXX impl-dep manner
@@ -338,7 +359,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         if not contextName:
             contextName = self._emptyStr
 
-        debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: using contextEngineId %r, contextName %r' % (contextEngineId, contextName))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareResponseMessage: using contextEngineId %r, contextName %r' % (contextEngineId, contextName))
 
         # 7.1.6
         scopedPDU = self.__scopedPDU
@@ -361,7 +383,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         # 7.1.7b
         headerData.setComponentByPosition(0, msgID, verifyConstraints=False)
 
-        snmpEngineMaxMessageSize, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
+        snmpEngineMaxMessageSize, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+            '__SNMP-FRAMEWORK-MIB', 'snmpEngineMaxMessageSize')
 
         # 7.1.7c
         # XXX need to coerce MIB value as it has incompatible constraints set
@@ -374,14 +397,14 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         if securityLevel == 1:
             pass
         elif securityLevel == 2:
-            msgFlags = msgFlags | 0x01
+            msgFlags |= 0x01
         elif securityLevel == 3:
-            msgFlags = msgFlags | 0x03
+            msgFlags |= 0x03
         else:
             raise error.ProtocolError('Unknown securityLevel %s' % securityLevel)
 
         if pdu.tagSet in rfc3411.confirmedClassPDUs:  # XXX not needed?
-            msgFlags = msgFlags | 0x04
+            msgFlags |= 0x04
 
         headerData.setComponentByPosition(
             2, self._msgFlags[msgFlags], verifyConstraints=False
@@ -399,17 +422,19 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         else:
             raise error.StatusInformation(errorIndication=errind.unsupportedSecurityModel)
 
-        debug.logger & debug.flagMP and debug.logger('prepareResponseMessage: securityModel %r, securityEngineId %r, securityName %r, securityLevel %r' % (securityModel, snmpEngineID, securityName, securityLevel))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareResponseMessage: securityModel %r, securityEngineId %r, securityName %r, securityLevel %r' % (
+                securityModel, snmpEngineID, securityName, securityLevel))
 
         # 7.1.8a
         try:
             (securityParameters,
              wholeMsg) = smHandler.generateResponseMsg(
-                 snmpEngine, self.messageProcessingModelID, msg,
-                 snmpEngineMaxMessageSize.syntax, securityModel,
-                 snmpEngineID, securityName, securityLevel, scopedPDU,
-                 securityStateReference
-             )
+                snmpEngine, self.messageProcessingModelID, msg,
+                snmpEngineMaxMessageSize.syntax, securityModel,
+                snmpEngineID, securityName, securityLevel, scopedPDU,
+                securityStateReference
+            )
         except error.StatusInformation:
             # 7.1.8.b
             raise
@@ -449,7 +474,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
 
         except PyAsn1Error:
             debug.logger & debug.flagMP and debug.logger('prepareDataElements: %s' % (sys.exc_info()[1],))
-            snmpInASNParseErrs, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB', 'snmpInASNParseErrs')
+            snmpInASNParseErrs, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMPv2-MIB',
+                                                                                                        'snmpInASNParseErrs')
             snmpInASNParseErrs.syntax += 1
             raise error.StatusInformation(errorIndication=errind.parseError)
 
@@ -467,11 +493,14 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         securityModel = headerData.getComponentByPosition(3)
         securityParameters = msg.getComponentByPosition(2)
 
-        debug.logger & debug.flagMP and debug.logger('prepareDataElements: msg data msgVersion %s msgID %s securityModel %s' % (msgVersion, msgID, securityModel))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareDataElements: msg data msgVersion %s msgID %s securityModel %s' % (
+                msgVersion, msgID, securityModel))
 
         # 7.2.4
         if securityModel not in snmpEngine.securityModels:
-            snmpUnknownSecurityModels, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-MPD-MIB', 'snmpUnknownSecurityModels')
+            snmpUnknownSecurityModels, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols(
+                '__SNMP-MPD-MIB', 'snmpUnknownSecurityModels')
             snmpUnknownSecurityModels.syntax += 1
             raise error.StatusInformation(errorIndication=errind.unsupportedSecurityModel)
 
@@ -483,7 +512,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         elif (msgFlags & 0x03) == 0x03:
             securityLevel = 3
         else:
-            snmpInvalidMsgs = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-MPD-MIB', 'snmpInvalidMsgs')
+            snmpInvalidMsgs = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-MPD-MIB',
+                                                                                                    'snmpInvalidMsgs')
             snmpInvalidMsgs.syntax += 1
             raise error.StatusInformation(errorIndication=errind.invalidMsg)
 
@@ -498,15 +528,16 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
             (securityEngineId, securityName,
              scopedPDU, maxSizeResponseScopedPDU,
              securityStateReference) = smHandler.processIncomingMsg(
-                 snmpEngine, messageProcessingModel, maxMessageSize,
-                 securityParameters, securityModel, securityLevel,
-                 wholeMsg, msg
-             )
+                snmpEngine, messageProcessingModel, maxMessageSize,
+                securityParameters, securityModel, securityLevel,
+                wholeMsg, msg
+            )
             debug.logger & debug.flagMP and debug.logger('prepareDataElements: SM succeeded')
 
         except error.StatusInformation:
             statusInformation, origTraceback = sys.exc_info()[1:3]
-            debug.logger & debug.flagMP and debug.logger('prepareDataElements: SM failed, statusInformation %s' % statusInformation)
+            debug.logger & debug.flagMP and debug.logger(
+                'prepareDataElements: SM failed, statusInformation %s' % statusInformation)
             if 'errorIndication' in statusInformation:
                 # 7.2.6a
                 if 'oid' in statusInformation:
@@ -579,14 +610,17 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
                         self.__engineIdCacheExpQueue[expireAt] = []
                     self.__engineIdCacheExpQueue[expireAt].append(k)
 
-                    debug.logger & debug.flagMP and debug.logger('prepareDataElements: cache securityEngineId %r for %r %r' % (securityEngineId, transportDomain, transportAddress))
+                    debug.logger & debug.flagMP and debug.logger(
+                        'prepareDataElements: cache securityEngineId %r for %r %r' % (
+                            securityEngineId, transportDomain, transportAddress))
 
-        snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB', 'snmpEngineID')
+        snmpEngineID, = snmpEngine.msgAndPduDsp.mibInstrumController.mibBuilder.importSymbols('__SNMP-FRAMEWORK-MIB',
+                                                                                              'snmpEngineID')
         snmpEngineID = snmpEngineID.syntax
 
         # 7.2.7 XXX PDU would be parsed here?
         contextEngineId, contextName, pdu = scopedPDU
-        pdu = pdu.getComponent() # PDUs
+        pdu = pdu.getComponent()  # PDUs
 
         # 7.2.8
         pduVersion = api.protoVersion2c
@@ -596,7 +630,7 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
 
         # 7.2.10
         if pduType in rfc3411.responseClassPDUs or \
-               pduType in rfc3411.internalClassPDUs:
+                pduType in rfc3411.internalClassPDUs:
             # 7.2.10a
             try:
                 cachedReqParams = self._cache.popByMsgId(msgID)
@@ -610,7 +644,8 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
         else:
             sendPduHandle = None
 
-        debug.logger & debug.flagMP and debug.logger('prepareDataElements: using sendPduHandle %s for msgID %s' % (sendPduHandle, msgID))
+        debug.logger & debug.flagMP and debug.logger(
+            'prepareDataElements: using sendPduHandle %s for msgID %s' % (sendPduHandle, msgID))
 
         # 7.2.11
         if pduType in rfc3411.internalClassPDUs:
@@ -623,6 +658,10 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
                     oid=varBinds[0][0], val=varBinds[0][1],
                     sendPduHandle=sendPduHandle
                 )
+            else:
+                statusInformation = error.StatusInformation(
+                    sendPduHandle=sendPduHandle
+                )
 
             # 7.2.11b (incomplete implementation)
 
@@ -646,7 +685,7 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
             smHandler.releaseStateInformation(securityStateReference)
 
             # 7.2.11d
-            stateReference = None
+            # no-op
 
             # 7.2.11e XXX may need to pass Reports up to app in some cases...
             raise statusInformation
@@ -658,11 +697,12 @@ class SnmpV3MessageProcessingModel(AbstractMessageProcessingModel):
             # 7.2.12a -> noop
 
             # 7.2.12b
+            # noinspection PyUnboundLocalVariable
             if securityModel != cachedReqParams['securityModel'] or \
-               securityName != cachedReqParams['securityName'] or \
-               securityLevel != cachedReqParams['securityLevel'] or \
-               contextEngineId != cachedReqParams['contextEngineId'] or \
-               contextName != cachedReqParams['contextName']:
+                    securityName != cachedReqParams['securityName'] or \
+                    securityLevel != cachedReqParams['securityLevel'] or \
+                    contextEngineId != cachedReqParams['contextEngineId'] or \
+                    contextName != cachedReqParams['contextName']:
                 smHandler.releaseStateInformation(securityStateReference)
                 raise error.StatusInformation(
                     errorIndication=errind.dataMismatch
diff --git a/pysnmp/proto/proxy/rfc2576.py b/pysnmp/proto/proxy/rfc2576.py
index 7d2f379d..771d6912 100644
--- a/pysnmp/proto/proxy/rfc2576.py
+++ b/pysnmp/proto/proxy/rfc2576.py
@@ -22,7 +22,7 @@ __v1ToV2ValueMap = {
     v1.Opaque.tagSet: v2c.Opaque()
 }
 
-__v2ToV1ValueMap = { # XXX do not re-create same-type items?
+__v2ToV1ValueMap = {  # XXX do not re-create same-type items?
     v2c.Integer32.tagSet: v1.Integer(),
     v2c.OctetString.tagSet: v1.OctetString(),
     v2c.Null.tagSet: v1.Null(),
@@ -50,7 +50,7 @@ __v2ToV1PduMap = {
     v2c.SetRequestPDU.tagSet: v1.SetRequestPDU(),
     v2c.ResponsePDU.tagSet: v1.GetResponsePDU(),
     v2c.SNMPv2TrapPDU.tagSet: v1.TrapPDU(),
-    v2c.GetBulkRequestPDU.tagSet: v1.GetNextRequestPDU() # 4.1.1
+    v2c.GetBulkRequestPDU.tagSet: v1.GetNextRequestPDU()  # 4.1.1
 }
 
 # Trap map
@@ -76,15 +76,15 @@ __v2ToV1TrapMap = {
 # 4.3
 
 __v2ToV1ErrorMap = {
-    0:  0,
-    1:  1,
-    5:  5,
+    0: 0,
+    1: 1,
+    5: 5,
     10: 3,
-    9:  3,
-    7:  3,
-    8:  3,
+    9: 3,
+    7: 3,
+    8: 3,
     12: 3,
-    6:  2,
+    6: 2,
     17: 2,
     11: 2,
     18: 2,
@@ -96,6 +96,7 @@ __v2ToV1ErrorMap = {
 
 __zeroInt = v1.Integer(0)
 
+
 def v1ToV2(v1Pdu, origV2Pdu=None):
     pduType = v1Pdu.tagSet
     v2Pdu = __v1ToV2PduMap[pduType].clone()
@@ -112,8 +113,7 @@ def v1ToV2(v1Pdu, origV2Pdu=None):
         # 3.1.2
         genericTrap = v1.apiTrapPDU.getGenericTrap(v1Pdu)
         if genericTrap == 6:
-            snmpTrapOIDParam = v1.apiTrapPDU.getEnterprise(v1Pdu) + (0,) + \
-                               (int(v1.apiTrapPDU.getSpecificTrap(v1Pdu)),)
+            snmpTrapOIDParam = v1.apiTrapPDU.getEnterprise(v1Pdu) + (0, int(v1.apiTrapPDU.getSpecificTrap(v1Pdu)))
 
         # 3.1.3
         else:
@@ -146,15 +146,11 @@ def v1ToV2(v1Pdu, origV2Pdu=None):
         # 4.1.2.2.1&2
         errorStatus = int(v1.apiPDU.getErrorStatus(v1Pdu))
         errorIndex = int(v1.apiPDU.getErrorIndex(v1Pdu, muteErrors=True))
-        if errorStatus == 2: # noSuchName
+        if errorStatus == 2:  # noSuchName
             if origV2Pdu.tagSet == v2c.GetNextRequestPDU.tagSet:
-                v2VarBinds = [
-                    (o, rfc1905.endOfMibView) for o, v in v2VarBinds
-                ]
+                v2VarBinds = [(o, rfc1905.endOfMibView) for o, v in v2VarBinds]
             else:
-                v2VarBinds = [
-                    (o, rfc1905.noSuchObject) for o, v in v2VarBinds
-                ]
+                v2VarBinds = [(o, rfc1905.noSuchObject) for o, v in v2VarBinds]
             v2c.apiPDU.setErrorStatus(v2Pdu, 0)
             v2c.apiPDU.setErrorIndex(v2Pdu, 0)
         else:
@@ -162,7 +158,7 @@ def v1ToV2(v1Pdu, origV2Pdu=None):
             v2c.apiPDU.setErrorStatus(v2Pdu, errorStatus)
             v2c.apiPDU.setErrorIndex(v2Pdu, errorIndex)
 
-        # 4.1.2.1 --> no-op
+            # 4.1.2.1 --> no-op
 
     elif pduType in rfc3411.confirmedClassPDUs:
         v2c.apiPDU.setErrorStatus(v2Pdu, 0)
@@ -177,6 +173,7 @@ def v1ToV2(v1Pdu, origV2Pdu=None):
 
     return v2Pdu
 
+
 def v2ToV1(v2Pdu, origV1Pdu=None):
     debug.logger & debug.flagPrx and debug.logger('v2ToV1: v2Pdu %s' % v2Pdu.prettyPrint())
 
@@ -238,9 +235,9 @@ def v2ToV1(v2Pdu, origV1Pdu=None):
         __v2VarBinds = []
         for oid, val in v2VarBinds[2:]:
             if oid in __v2ToV1TrapMap or \
-                   oid in (v2c.apiTrapPDU.sysUpTime,
-                           v2c.apiTrapPDU.snmpTrapAddress,
-                           v2c.apiTrapPDU.snmpTrapEnterprise):
+                    oid in (v2c.apiTrapPDU.sysUpTime,
+                            v2c.apiTrapPDU.snmpTrapAddress,
+                            v2c.apiTrapPDU.snmpTrapEnterprise):
                 continue
             __v2VarBinds.append((oid, val))
         v2VarBinds = __v2VarBinds
@@ -252,14 +249,14 @@ def v2ToV1(v2Pdu, origV1Pdu=None):
         v1.apiPDU.setErrorIndex(v1Pdu, __zeroInt)
 
     if pduType in rfc3411.responseClassPDUs:
-        idx = len(v2VarBinds)-1
+        idx = len(v2VarBinds) - 1
         while idx >= 0:
             # 4.1.2.1
             oid, val = v2VarBinds[idx]
             if v2c.Counter64.tagSet == val.tagSet:
                 if origV1Pdu.tagSet == v1.GetRequestPDU.tagSet:
                     v1.apiPDU.setErrorStatus(v1Pdu, 2)
-                    v1.apiPDU.setErrorIndex(v1Pdu, idx+1)
+                    v1.apiPDU.setErrorIndex(v1Pdu, idx + 1)
                     break
                 elif origV1Pdu.tagSet == v1.GetNextRequestPDU.tagSet:
                     raise error.StatusInformation(idx=idx, pdu=v2Pdu)
@@ -271,7 +268,7 @@ def v2ToV1(v2Pdu, origV1Pdu=None):
                               v2c.NoSuchInstance.tagSet,
                               v2c.EndOfMibView.tagSet):
                 v1.apiPDU.setErrorStatus(v1Pdu, 2)
-                v1.apiPDU.setErrorIndex(v1Pdu, idx+1)
+                v1.apiPDU.setErrorIndex(v1Pdu, idx + 1)
 
             idx -= 1
 
@@ -280,7 +277,7 @@ def v2ToV1(v2Pdu, origV1Pdu=None):
         if v2ErrorStatus:
             v1.apiPDU.setErrorStatus(
                 v1Pdu, __v2ToV1ErrorMap.get(v2ErrorStatus, 5)
-                )
+            )
             v1.apiPDU.setErrorIndex(v1Pdu, v2c.apiPDU.getErrorIndex(v2Pdu, muteErrors=True))
 
     elif pduType in rfc3411.confirmedClassPDUs:
@@ -289,7 +286,7 @@ def v2ToV1(v2Pdu, origV1Pdu=None):
 
     # Translate Var-Binds
     if pduType in rfc3411.responseClassPDUs and \
-           v1.apiPDU.getErrorStatus(v1Pdu):
+            v1.apiPDU.getErrorStatus(v1Pdu):
         v1VarBinds = v1.apiPDU.getVarBinds(origV1Pdu)
     else:
         for oid, v2Val in v2VarBinds:
diff --git a/pysnmp/proto/rfc1157.py b/pysnmp/proto/rfc1157.py
index 5bf3d429..97b4215a 100644
--- a/pysnmp/proto/rfc1157.py
+++ b/pysnmp/proto/rfc1157.py
@@ -18,12 +18,12 @@ class VarBind(univ.Sequence):
 class VarBindList(univ.SequenceOf):
     componentType = VarBind()
 
-_errorStatus = univ.Integer(namedValues=namedval.NamedValues(('noError', 0), ('tooBig', 1), ('noSuchName', 2), ('badValue', 3), ('readOnly', 4), ('genErr', 5)))
+errorStatus = univ.Integer(namedValues=namedval.NamedValues(('noError', 0), ('tooBig', 1), ('noSuchName', 2), ('badValue', 3), ('readOnly', 4), ('genErr', 5)))
 
 class _RequestBase(univ.Sequence):
     componentType = namedtype.NamedTypes(
         namedtype.NamedType('request-id', univ.Integer()),
-        namedtype.NamedType('error-status', _errorStatus),
+        namedtype.NamedType('error-status', errorStatus),
         namedtype.NamedType('error-index', univ.Integer()),
         namedtype.NamedType('variable-bindings', VarBindList())
     )
@@ -45,7 +45,7 @@ class SetRequestPDU(_RequestBase):
         tag.Tag(tag.tagClassContext, tag.tagFormatConstructed, 3)
     )
 
-_genericTrap = univ.Integer().clone(namedValues=namedval.NamedValues(('coldStart', 0), ('warmStart', 1), ('linkDown', 2), ('linkUp', 3), ('authenticationFailure', 4), ('egpNeighborLoss', 5), ('enterpriseSpecific', 6)))
+genericTrap = univ.Integer().clone(namedValues=namedval.NamedValues(('coldStart', 0), ('warmStart', 1), ('linkDown', 2), ('linkUp', 3), ('authenticationFailure', 4), ('egpNeighborLoss', 5), ('enterpriseSpecific', 6)))
 
 class TrapPDU(univ.Sequence):
     tagSet = univ.Sequence.tagSet.tagImplicitly(
@@ -54,7 +54,7 @@ class TrapPDU(univ.Sequence):
     componentType = namedtype.NamedTypes(
         namedtype.NamedType('enterprise', univ.ObjectIdentifier()),
         namedtype.NamedType('agent-addr', rfc1155.NetworkAddress()),
-        namedtype.NamedType('generic-trap', _genericTrap),
+        namedtype.NamedType('generic-trap', genericTrap),
         namedtype.NamedType('specific-trap', univ.Integer()),
         namedtype.NamedType('time-stamp', rfc1155.TimeTicks()),
         namedtype.NamedType('variable-bindings', VarBindList())
@@ -69,11 +69,11 @@ class PDUs(univ.Choice):
         namedtype.NamedType('trap', TrapPDU())
     )
 
-_version = univ.Integer(namedValues=namedval.NamedValues(('version-1', 0)))
+version = univ.Integer(namedValues=namedval.NamedValues(('version-1', 0)))
 
 class Message(univ.Sequence):
     componentType = namedtype.NamedTypes(
-        namedtype.NamedType('version', _version),
+        namedtype.NamedType('version', version),
         namedtype.NamedType('community', univ.OctetString()),
         namedtype.NamedType('data', PDUs())
     )
diff --git a/pysnmp/proto/rfc1901.py b/pysnmp/proto/rfc1901.py
index 996fb629..ca72301b 100644
--- a/pysnmp/proto/rfc1901.py
+++ b/pysnmp/proto/rfc1901.py
@@ -7,11 +7,11 @@
 from pyasn1.type import univ, namedtype, namedval
 from pysnmp.proto import rfc1905
 
-_version = univ.Integer(namedValues=namedval.NamedValues(('version-2c', 1)))
+version = univ.Integer(namedValues=namedval.NamedValues(('version-2c', 1)))
 
 class Message(univ.Sequence):
     componentType = namedtype.NamedTypes(
-        namedtype.NamedType('version', _version),
+        namedtype.NamedType('version', version),
         namedtype.NamedType('community', univ.OctetString()),
         namedtype.NamedType('data', rfc1905.PDUs())
     )
diff --git a/pysnmp/proto/rfc1905.py b/pysnmp/proto/rfc1905.py
index b8189a3f..0b7136a8 100644
--- a/pysnmp/proto/rfc1905.py
+++ b/pysnmp/proto/rfc1905.py
@@ -72,26 +72,26 @@ class VarBindList(univ.SequenceOf):
         0, max_bindings
     )
 
-_errorStatus = univ.Integer(namedValues=namedval.NamedValues(('noError', 0), ('tooBig', 1), ('noSuchName', 2), ('badValue', 3), ('readOnly', 4), ('genErr', 5), ('noAccess', 6), ('wrongType', 7), ('wrongLength', 8), ('wrongEncoding', 9), ('wrongValue', 10), ('noCreation', 11), ('inconsistentValue', 12), ('resourceUnavailable', 13), ('commitFailed', 14), ('undoFailed', 15), ('authorizationError', 16), ('notWritable', 17), ('inconsistentName', 18)))
+errorStatus = univ.Integer(namedValues=namedval.NamedValues(('noError', 0), ('tooBig', 1), ('noSuchName', 2), ('badValue', 3), ('readOnly', 4), ('genErr', 5), ('noAccess', 6), ('wrongType', 7), ('wrongLength', 8), ('wrongEncoding', 9), ('wrongValue', 10), ('noCreation', 11), ('inconsistentValue', 12), ('resourceUnavailable', 13), ('commitFailed', 14), ('undoFailed', 15), ('authorizationError', 16), ('notWritable', 17), ('inconsistentName', 18)))
 
 # Base class for a non-bulk PDU
 class PDU(univ.Sequence):
     componentType = namedtype.NamedTypes(
         namedtype.NamedType('request-id', rfc1902.Integer32()),
-        namedtype.NamedType('error-status', _errorStatus),
+        namedtype.NamedType('error-status', errorStatus),
         namedtype.NamedType('error-index', univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, max_bindings))),
         namedtype.NamedType('variable-bindings', VarBindList())
     )
 
-_nonRepeaters = univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, max_bindings))
-_maxRepetitions = univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, max_bindings))
+nonRepeaters = univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, max_bindings))
+maxRepetitions = univ.Integer().subtype(subtypeSpec=constraint.ValueRangeConstraint(0, max_bindings))
 
 # Base class for bulk PDU
 class BulkPDU(univ.Sequence):
     componentType = namedtype.NamedTypes(
         namedtype.NamedType('request-id', rfc1902.Integer32()),
-        namedtype.NamedType('non-repeaters', _nonRepeaters),
-        namedtype.NamedType('max-repetitions', _maxRepetitions),
+        namedtype.NamedType('non-repeaters', nonRepeaters),
+        namedtype.NamedType('max-repetitions', maxRepetitions),
         namedtype.NamedType('variable-bindings', VarBindList())
     )
 
diff --git a/pysnmp/proto/secmod/eso/priv/aes192.py b/pysnmp/proto/secmod/eso/priv/aes192.py
index 1fc08d4b..0de69551 100644
--- a/pysnmp/proto/secmod/eso/priv/aes192.py
+++ b/pysnmp/proto/secmod/eso/priv/aes192.py
@@ -6,6 +6,7 @@
 #
 from pysnmp.proto.secmod.eso.priv import aesbase
 
+
 class Aes192(aesbase.AbstractAes):
     """AES 192/256 bit encryption (Internet draft)
 
diff --git a/pysnmp/proto/secmod/eso/priv/aes256.py b/pysnmp/proto/secmod/eso/priv/aes256.py
index 4d5cbc71..c6ec1ab9 100644
--- a/pysnmp/proto/secmod/eso/priv/aes256.py
+++ b/pysnmp/proto/secmod/eso/priv/aes256.py
@@ -6,6 +6,7 @@
 #
 from pysnmp.proto.secmod.eso.priv import aesbase
 
+
 class Aes256(aesbase.AbstractAes):
     """AES 192/256 bit encryption (Internet draft)
 
diff --git a/pysnmp/proto/secmod/eso/priv/aesbase.py b/pysnmp/proto/secmod/eso/priv/aesbase.py
index 921b0197..f67bdfe0 100644
--- a/pysnmp/proto/secmod/eso/priv/aesbase.py
+++ b/pysnmp/proto/secmod/eso/priv/aesbase.py
@@ -9,13 +9,17 @@ from pysnmp.proto.secmod.rfc3414.auth import hmacmd5, hmacsha
 from pysnmp.proto.secmod.rfc3414 import localkey
 from pysnmp.proto import error
 from math import ceil
+
 try:
     from hashlib import md5, sha1
 except ImportError:
-    import md5, sha
+    import md5
+    import sha
+
     md5 = md5.new
     sha1 = sha.new
 
+
 class AbstractAes(aes.Aes):
     serviceID = ()
     keySize = 0
@@ -24,14 +28,15 @@ class AbstractAes(aes.Aes):
     def localizeKey(self, authProtocol, privKey, snmpEngineID):
         if authProtocol == hmacmd5.HmacMd5.serviceID:
             localPrivKey = localkey.localizeKeyMD5(privKey, snmpEngineID)
-            while ceil(self.keySize//len(localPrivKey)):
+            while ceil(self.keySize // len(localPrivKey)):
+                # noinspection PyDeprecation,PyCallingNonCallable
                 localPrivKey = localPrivKey + md5(localPrivKey).digest()
         elif authProtocol == hmacsha.HmacSha.serviceID:
             localPrivKey = localkey.localizeKeySHA(privKey, snmpEngineID)
-            while ceil(self.keySize//len(localPrivKey)):
+            while ceil(self.keySize // len(localPrivKey)):
                 localPrivKey = localPrivKey + sha1(localPrivKey).digest()
         else:
             raise error.ProtocolError(
                 'Unknown auth protocol %s' % (authProtocol,)
-                )
+            )
         return localPrivKey[:self.keySize]
diff --git a/pysnmp/proto/secmod/eso/priv/des3.py b/pysnmp/proto/secmod/eso/priv/des3.py
index 8b4b19d3..e91f8fed 100644
--- a/pysnmp/proto/secmod/eso/priv/des3.py
+++ b/pysnmp/proto/secmod/eso/priv/des3.py
@@ -16,7 +16,9 @@ from math import ceil
 try:
     from hashlib import md5, sha1
 except ImportError:
-    import md5, sha
+    import md5
+    import sha
+
     md5 = md5.new
     sha1 = sha.new
 
@@ -27,6 +29,7 @@ except ImportError:
 
 random.seed()
 
+
 # 5.1.1
 
 class Des3(base.AbstractEncryptionService):
@@ -34,7 +37,7 @@ class Des3(base.AbstractEncryptionService):
 
        http://www.snmp.com/eso/draft-reeder-snmpv3-usm-3desede-00.txt
     """
-    serviceID = (1, 3, 6, 1, 6, 3, 10, 1, 2, 3) # usm3DESEDEPrivProtocol
+    serviceID = (1, 3, 6, 1, 6, 3, 10, 1, 2, 3)  # usm3DESEDEPrivProtocol
     keySize = 32
     _localInt = random.randrange(0, 0xffffffff)
 
@@ -46,22 +49,23 @@ class Des3(base.AbstractEncryptionService):
         else:
             raise error.ProtocolError(
                 'Unknown auth protocol %s' % (authProtocol,)
-                )
+            )
 
     def localizeKey(self, authProtocol, privKey, snmpEngineID):
         if authProtocol == hmacmd5.HmacMd5.serviceID:
             localPrivKey = localkey.localizeKeyMD5(privKey, snmpEngineID)
-            while ceil(self.keySize//len(localPrivKey)):
+            while ceil(self.keySize // len(localPrivKey)):
+                # noinspection PyDeprecation,PyCallingNonCallable
                 localPrivKey = localPrivKey + md5(localPrivKey).digest()
         elif authProtocol == hmacsha.HmacSha.serviceID:
             localPrivKey = localkey.localizeKeySHA(privKey, snmpEngineID)
-            while ceil(self.keySize//len(localPrivKey)):
+            while ceil(self.keySize // len(localPrivKey)):
                 localPrivKey = localPrivKey + sha1(localPrivKey).digest()
         else:
             raise error.ProtocolError(
                 'Unknown auth protocol %s' % (authProtocol,)
-                )
-        return localPrivKey[:self.keySize] # key+IV
+            )
+        return localPrivKey[:self.keySize]  # key+IV
 
     # 5.1.1.1
     def __getEncryptionKey(self, privKey, snmpEngineBoots):
@@ -72,42 +76,43 @@ class Des3(base.AbstractEncryptionService):
         securityEngineBoots = int(snmpEngineBoots)
 
         salt = [
-            securityEngineBoots>>24&0xff,
-            securityEngineBoots>>16&0xff,
-            securityEngineBoots>>8&0xff,
-            securityEngineBoots&0xff,
-            self._localInt>>24&0xff,
-            self._localInt>>16&0xff,
-            self._localInt>>8&0xff,
-            self._localInt&0xff
-            ]
+            securityEngineBoots >> 24 & 0xff,
+            securityEngineBoots >> 16 & 0xff,
+            securityEngineBoots >> 8 & 0xff,
+            securityEngineBoots & 0xff,
+            self._localInt >> 24 & 0xff,
+            self._localInt >> 16 & 0xff,
+            self._localInt >> 8 & 0xff,
+            self._localInt & 0xff
+        ]
         if self._localInt == 0xffffffff:
             self._localInt = 0
         else:
-            self._localInt = self._localInt + 1
+            self._localInt += 1
 
         # salt not yet hashed XXX
 
-        return des3Key.asOctets(), \
-               univ.OctetString(salt).asOctets(), \
-               univ.OctetString(map(lambda x, y: x^y, salt, preIV.asNumbers())).asOctets()
+        return (des3Key.asOctets(),
+                univ.OctetString(salt).asOctets(),
+                univ.OctetString(map(lambda x, y: x ^ y, salt, preIV.asNumbers())).asOctets())
 
-    def __getDecryptionKey(self, privKey, salt):
-        return privKey[:24].asOctets(), \
-               univ.OctetString(map(lambda x, y: x^y, salt.asNumbers(), privKey[24:32].asNumbers())).asOctets()
+    @staticmethod
+    def __getDecryptionKey(privKey, salt):
+        return (privKey[:24].asOctets(),
+                univ.OctetString(map(lambda x, y: x ^ y, salt.asNumbers(), privKey[24:32].asNumbers())).asOctets())
 
     # 5.1.1.2
     def encryptData(self, encryptKey, privParameters, dataToEncrypt):
         if DES3 is None:
             raise error.StatusInformation(
                 errorIndication=errind.encryptionError
-                )
+            )
 
         snmpEngineBoots, snmpEngineTime, salt = privParameters
 
         des3Key, salt, iv = self.__getEncryptionKey(
             encryptKey, snmpEngineBoots
-            )
+        )
 
         des3Obj = DES3.new(des3Key, DES3.MODE_CBC, iv)
 
@@ -118,8 +123,9 @@ class Des3(base.AbstractEncryptionService):
         ciphertext = null
         while plaintext:
             cipherblock = des3Obj.encrypt(
-                univ.OctetString(map(lambda x, y: x^y, univ.OctetString(cipherblock).asNumbers(), univ.OctetString(plaintext[:8]).asNumbers())).asOctets()
-                )
+                univ.OctetString(map(lambda x, y: x ^ y, univ.OctetString(cipherblock).asNumbers(),
+                                     univ.OctetString(plaintext[:8]).asNumbers())).asOctets()
+            )
             ciphertext = ciphertext + cipherblock
             plaintext = plaintext[8:]
 
@@ -130,20 +136,20 @@ class Des3(base.AbstractEncryptionService):
         if DES3 is None:
             raise error.StatusInformation(
                 errorIndication=errind.decryptionError
-                )
+            )
         snmpEngineBoots, snmpEngineTime, salt = privParameters
 
         if len(salt) != 8:
             raise error.StatusInformation(
                 errorIndication=errind.decryptionError
-                )
+            )
 
         des3Key, iv = self.__getDecryptionKey(decryptKey, salt)
 
         if len(encryptedData) % 8 != 0:
             raise error.StatusInformation(
                 errorIndication=errind.decryptionError
-                )
+            )
 
         des3Obj = DES3.new(des3Key, DES3.MODE_CBC, iv)
 
@@ -151,7 +157,9 @@ class Des3(base.AbstractEncryptionService):
         ciphertext = encryptedData.asOctets()
         cipherblock = iv
         while ciphertext:
-            plaintext = plaintext + univ.OctetString(map(lambda x, y: x ^ y, univ.OctetString(cipherblock).asNumbers(), univ.OctetString(des3Obj.decrypt(ciphertext[:8])).asNumbers())).asOctets()
+            plaintext = plaintext + univ.OctetString(map(lambda x, y: x ^ y, univ.OctetString(cipherblock).asNumbers(),
+                                                         univ.OctetString(
+                                                             des3Obj.decrypt(ciphertext[:8])).asNumbers())).asOctets()
             cipherblock = ciphertext[:8]
             ciphertext = ciphertext[8:]
 
diff --git a/pysnmp/proto/secmod/rfc3414/auth/base.py b/pysnmp/proto/secmod/rfc3414/auth/base.py
index 4f57559d..9f842fe5 100644
--- a/pysnmp/proto/secmod/rfc3414/auth/base.py
+++ b/pysnmp/proto/secmod/rfc3414/auth/base.py
@@ -6,6 +6,7 @@
 #
 from pysnmp.proto import errind, error
 
+
 class AbstractAuthenticationService:
     serviceID = None