Uppercase global constants (#238)

This is a massive patch essentially upper-casing global/class attributes
that mean to be constants.

Some previously exposed constants have been preserved for compatibility
reasons (notably, in `hlapi`), though the rest might break user code relying
on pysnmp 4.

18 files changed, 94 insertions, 85 deletions

diff --git a/pysnmp/carrier/asyncio/base.py b/pysnmp/carrier/asyncio/base.py
index ce1b644f..4ee21ead 100644
--- a/pysnmp/carrier/asyncio/base.py
+++ b/pysnmp/carrier/asyncio/base.py
@@ -35,5 +35,5 @@ from pysnmp.carrier.base import AbstractTransport
 
 
 class AbstractAsyncioTransport(AbstractTransport):
-    protoTransportDispatcher = AsyncioDispatcher
+    PROTO_TRANSPORT_DISPATCHER = 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 a845fa1e..7cc0b589 100644
--- a/pysnmp/carrier/asyncio/dgram/base.py
+++ b/pysnmp/carrier/asyncio/dgram/base.py
@@ -47,8 +47,9 @@ IS_PYTHON_344_PLUS = platform.python_version_tuple() >= ('3', '4', '4')
 
 class DgramAsyncioProtocol(asyncio.DatagramProtocol, AbstractAsyncioTransport):
     """Base Asyncio datagram Transport, to be used with AsyncioDispatcher"""
-    sockFamily = None
-    addressType = lambda x: x
+    SOCK_FAMILY = None
+    ADDRESS_TYPE = lambda x: x
+
     transport = None
 
     def __init__(self, sock=None, sockMap=None, loop=None):
@@ -66,25 +67,25 @@ class DgramAsyncioProtocol(asyncio.DatagramProtocol, AbstractAsyncioTransport):
 
     def connection_made(self, transport):
         self.transport = transport
-        debug.logger & debug.flagIO and debug.logger('connection_made: invoked')
+        debug.logger & debug.FLAG_IO and debug.logger('connection_made: invoked')
         while self._writeQ:
             outgoingMessage, transportAddress = self._writeQ.pop(0)
-            debug.logger & debug.flagIO and debug.logger('connection_made: transportAddress %r outgoingMessage %s' %
-                                                         (transportAddress, debug.hexdump(outgoingMessage)))
+            debug.logger & debug.FLAG_IO and debug.logger('connection_made: transportAddress %r outgoingMessage %s' %
+                                                          (transportAddress, debug.hexdump(outgoingMessage)))
             try:
                 self.transport.sendto(outgoingMessage, self.normalizeAddress(transportAddress))
             except Exception:
                 raise error.CarrierError(';'.join(traceback.format_exception(*sys.exc_info())))
 
     def connection_lost(self, exc):
-        debug.logger & debug.flagIO and debug.logger('connection_lost: invoked')
+        debug.logger & debug.FLAG_IO and debug.logger('connection_lost: invoked')
 
     # AbstractAsyncioTransport API
 
     def openClientMode(self, iface=None):
         try:
             c = self.loop.create_datagram_endpoint(
-                lambda: self, local_addr=iface, family=self.sockFamily
+                lambda: self, local_addr=iface, family=self.SOCK_FAMILY
             )
             # Avoid deprecation warning for asyncio.async()
             if IS_PYTHON_344_PLUS:
@@ -99,7 +100,7 @@ class DgramAsyncioProtocol(asyncio.DatagramProtocol, AbstractAsyncioTransport):
     def openServerMode(self, iface):
         try:
             c = self.loop.create_datagram_endpoint(
-                lambda: self, local_addr=iface, family=self.sockFamily
+                lambda: self, local_addr=iface, family=self.SOCK_FAMILY
             )
             # Avoid deprecation warning for asyncio.async()
             if IS_PYTHON_344_PLUS:
@@ -118,7 +119,7 @@ class DgramAsyncioProtocol(asyncio.DatagramProtocol, AbstractAsyncioTransport):
         AbstractAsyncioTransport.closeTransport(self)
 
     def sendMessage(self, outgoingMessage, transportAddress):
-        debug.logger & debug.flagIO and debug.logger('sendMessage: %s transportAddress %r outgoingMessage %s' % (
+        debug.logger & debug.FLAG_IO and debug.logger('sendMessage: %s transportAddress %r outgoingMessage %s' % (
             (self.transport is None and "queuing" or "sending"),
             transportAddress, debug.hexdump(outgoingMessage)
         ))
@@ -131,6 +132,6 @@ class DgramAsyncioProtocol(asyncio.DatagramProtocol, AbstractAsyncioTransport):
                 raise error.CarrierError(';'.join(traceback.format_exception(*sys.exc_info())))
 
     def normalizeAddress(self, transportAddress):
-        if not isinstance(transportAddress, self.addressType):
-            transportAddress = self.addressType(transportAddress)
+        if not isinstance(transportAddress, self.ADDRESS_TYPE):
+            transportAddress = self.ADDRESS_TYPE(transportAddress)
         return transportAddress
diff --git a/pysnmp/carrier/asyncio/dgram/udp.py b/pysnmp/carrier/asyncio/dgram/udp.py
index 41ada723..b13d4202 100644
--- a/pysnmp/carrier/asyncio/dgram/udp.py
+++ b/pysnmp/carrier/asyncio/dgram/udp.py
@@ -42,8 +42,8 @@ class UdpTransportAddress(tuple, AbstractTransportAddress):
 
 
 class UdpAsyncioTransport(DgramAsyncioProtocol):
-    sockFamily = socket.AF_INET
-    addressType = UdpTransportAddress
+    SOCK_FAMILY = socket.AF_INET
+    ADDRESS_TYPE = UdpTransportAddress
 
 
 UdpTransport = UdpAsyncioTransport
diff --git a/pysnmp/carrier/asyncio/dgram/udp6.py b/pysnmp/carrier/asyncio/dgram/udp6.py
index bc03b447..f3708852 100644
--- a/pysnmp/carrier/asyncio/dgram/udp6.py
+++ b/pysnmp/carrier/asyncio/dgram/udp6.py
@@ -17,8 +17,8 @@ class Udp6TransportAddress(tuple, AbstractTransportAddress):
 
 
 class Udp6AsyncioTransport(DgramAsyncioProtocol):
-    sockFamily = socket.has_ipv6 and socket.AF_INET6 or None
-    addressType = Udp6TransportAddress
+    SOCK_FAMILY = socket.has_ipv6 and socket.AF_INET6 or None
+    ADDRESS_TYPE = Udp6TransportAddress
 
     def normalizeAddress(self, transportAddress):
         if '%' in transportAddress[0]:  # strip zone ID
diff --git a/pysnmp/carrier/asyncore/base.py b/pysnmp/carrier/asyncore/base.py
index e4824f32..035dcbab 100644
--- a/pysnmp/carrier/asyncore/base.py
+++ b/pysnmp/carrier/asyncore/base.py
@@ -14,37 +14,37 @@ from pysnmp import debug
 
 
 class AbstractSocketTransport(asyncore.dispatcher, AbstractTransport):
-    protoTransportDispatcher = AsyncoreDispatcher
-    sockFamily = sockType = None
-    retryCount = 0
-    retryInterval = 0
-    bufferSize = 131070
+    PROTO_TRANSPORT_DISPATCHER = AsyncoreDispatcher
+    SOCK_FAMILY = SOCK_TYPE = None
+    RETRY_COUNT = 0
+    RETRY_INTERVAL = 0
+    BUFFER_SIZE = 131070
 
     # noinspection PyUnusedLocal
     def __init__(self, sock=None, sockMap=None):
         asyncore.dispatcher.__init__(self)
         if sock is None:
-            if self.sockFamily is None:
+            if self.SOCK_FAMILY is None:
                 raise error.CarrierError(
                     'Address family %s not supported' % self.__class__.__name__
                 )
-            if self.sockType is None:
+            if self.SOCK_TYPE is None:
                 raise error.CarrierError(
                     'Socket type %s not supported' % self.__class__.__name__
                 )
             try:
-                sock = socket.socket(self.sockFamily, self.sockType)
+                sock = socket.socket(self.SOCK_FAMILY, self.SOCK_TYPE)
             except socket.error as exc:
                 raise error.CarrierError('socket() failed: %s' % exc)
 
             try:
                 for b in socket.SO_RCVBUF, socket.SO_SNDBUF:
                     bsize = sock.getsockopt(socket.SOL_SOCKET, b)
-                    if bsize < self.bufferSize:
-                        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))
+                    if bsize < self.BUFFER_SIZE:
+                        sock.setsockopt(socket.SOL_SOCKET, b, self.BUFFER_SIZE)
+                        debug.logger & debug.FLAG_IO and debug.logger('%s: socket %d buffer size increased from %d to %d for buffer %d' % (self.__class__.__name__, sock.fileno(), bsize, self.BUFFER_SIZE, b))
             except Exception as exc:
-                debug.logger & debug.flagIO and debug.logger('%s: socket buffer size option mangling failure for buffer: %s' % (self.__class__.__name__, exc))
+                debug.logger & debug.FLAG_IO and debug.logger('%s: socket buffer size option mangling failure for buffer: %s' % (self.__class__.__name__, exc))
 
         # The socket map is managed by the AsyncoreDispatcher on
         # which this transport is registered. Here we just prepare
@@ -82,8 +82,10 @@ class AbstractSocketTransport(asyncore.dispatcher, AbstractTransport):
         self.close()
 
     # asyncore API
+
     def handle_close(self):
         raise error.CarrierError('Transport unexpectedly closed')
 
     def handle_error(self):
-        raise
+        exc = sys.exc_info()[1]
+        raise exc
diff --git a/pysnmp/carrier/asyncore/dgram/base.py b/pysnmp/carrier/asyncore/dgram/base.py
index e9ffc9b0..f103e781 100644
--- a/pysnmp/carrier/asyncore/dgram/base.py
+++ b/pysnmp/carrier/asyncore/dgram/base.py
@@ -12,23 +12,23 @@ from pysnmp.carrier import sockfix, sockmsg, error
 from pysnmp import debug
 
 # Ignore these socket errors
-sockErrors = {errno.ESHUTDOWN: True,
-              errno.ENOTCONN: True,
-              errno.ECONNRESET: False,
-              errno.ECONNREFUSED: False,
-              errno.EAGAIN: False,
-              errno.EWOULDBLOCK: False}
+SOCK_ERRORS = {errno.ESHUTDOWN: True,
+               errno.ENOTCONN: True,
+               errno.ECONNRESET: False,
+               errno.ECONNREFUSED: False,
+               errno.EAGAIN: False,
+               errno.EWOULDBLOCK: False}
 
 if hasattr(errno, 'EBADFD'):
     # bad FD may happen upon FD closure on n-1 select() event
-    sockErrors[errno.EBADFD] = True
+    SOCK_ERRORS[errno.EBADFD] = True
 
 
 class DgramSocketTransport(AbstractSocketTransport):
-    sockType = socket.SOCK_DGRAM
-    retryCount = 3
-    retryInterval = 1
-    addressType = lambda x: x
+    SOCK_TYPE = socket.SOCK_DGRAM
+    RETRY_COUNT = 3
+    RETRY_INTERVAL = 1
+    ADDRESS_TYPE = lambda x: x
 
     def __init__(self, sock=None, sockMap=None):
         self.__outQueue = []
@@ -36,7 +36,7 @@ class DgramSocketTransport(AbstractSocketTransport):
 
         def __recvfrom(s, sz):
             d, a = s.recvfrom(sz)
-            return d, self.addressType(a)
+            return d, self.ADDRESS_TYPE(a)
 
         self._recvfrom = __recvfrom
         AbstractSocketTransport.__init__(self, sock, sockMap)
@@ -64,7 +64,7 @@ class DgramSocketTransport(AbstractSocketTransport):
             )
         except socket.error as exc:
             raise error.CarrierError('setsockopt() for SO_BROADCAST failed: %s' % exc)
-        debug.logger & debug.flagIO and debug.logger('enableBroadcast: %s option SO_BROADCAST on socket %s' % (flag and "enabled" or "disabled", self.socket.fileno()))
+        debug.logger & debug.FLAG_IO and debug.logger('enableBroadcast: %s option SO_BROADCAST on socket %s' % (flag and "enabled" or "disabled", self.socket.fileno()))
         return self
 
     def enablePktInfo(self, flag=1):
@@ -82,10 +82,10 @@ class DgramSocketTransport(AbstractSocketTransport):
         except socket.error as exc:
             raise error.CarrierError('setsockopt() for %s failed: %s' % (self.socket.family == socket.AF_INET6 and "IPV6_RECVPKTINFO" or "IP_PKTINFO", exc))
 
-        self._sendto = sockmsg.getSendTo(self.addressType)
-        self._recvfrom = sockmsg.getRecvFrom(self.addressType)
+        self._sendto = sockmsg.getSendTo(self.ADDRESS_TYPE)
+        self._recvfrom = sockmsg.getRecvFrom(self.ADDRESS_TYPE)
 
-        debug.logger & debug.flagIO and debug.logger('enablePktInfo: %s option %s on socket %s' % (self.socket.family == socket.AF_INET6 and "IPV6_RECVPKTINFO" or "IP_PKTINFO", flag and "enabled" or "disabled", self.socket.fileno()))
+        debug.logger & debug.FLAG_IO and debug.logger('enablePktInfo: %s option %s on socket %s' % (self.socket.family == socket.AF_INET6 and "IPV6_RECVPKTINFO" or "IP_PKTINFO", flag and "enabled" or "disabled", self.socket.fileno()))
         return self
 
     def enableTransparent(self, flag=1):
@@ -105,18 +105,18 @@ class DgramSocketTransport(AbstractSocketTransport):
         except OSError:
             raise error.CarrierError('IP_TRANSPARENT socket option requires superuser priveleges')
 
-        debug.logger & debug.flagIO and debug.logger('enableTransparent: %s option IP_TRANSPARENT on socket %s' % (flag and "enabled" or "disabled", self.socket.fileno()))
+        debug.logger & debug.FLAG_IO and debug.logger('enableTransparent: %s option IP_TRANSPARENT on socket %s' % (flag and "enabled" or "disabled", self.socket.fileno()))
         return self
 
     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)))
+        debug.logger & debug.FLAG_IO and debug.logger('sendMessage: outgoingMessage queued (%d octets) %s' % (len(outgoingMessage), debug.hexdump(outgoingMessage)))
 
     def normalizeAddress(self, transportAddress):
-        if not isinstance(transportAddress, self.addressType):
-            transportAddress = self.addressType(transportAddress)
+        if not isinstance(transportAddress, self.ADDRESS_TYPE):
+            transportAddress = self.ADDRESS_TYPE(transportAddress)
 
         if not transportAddress.getLocalAddress():
             transportAddress.setLocalAddress(self.getLocalAddress())
@@ -140,17 +140,17 @@ class DgramSocketTransport(AbstractSocketTransport):
 
     def handle_write(self):
         outgoingMessage, transportAddress = self.__outQueue.pop(0)
-        debug.logger & debug.flagIO and debug.logger('handle_write: transportAddress %r -> %r outgoingMessage (%d octets) %s' % (transportAddress.getLocalAddress(), transportAddress, len(outgoingMessage), debug.hexdump(outgoingMessage)))
+        debug.logger & debug.FLAG_IO and debug.logger('handle_write: transportAddress %r -> %r outgoingMessage (%d octets) %s' % (transportAddress.getLocalAddress(), transportAddress, len(outgoingMessage), debug.hexdump(outgoingMessage)))
         if not transportAddress:
-            debug.logger & debug.flagIO and debug.logger('handle_write: missing dst address, loosing outgoing msg')
+            debug.logger & debug.FLAG_IO and debug.logger('handle_write: missing dst address, loosing outgoing msg')
             return
         try:
             self._sendto(
                 self.socket, outgoingMessage, transportAddress
             )
         except socket.error as exc:
-            if exc.args[0] in sockErrors:
-                debug.logger & debug.flagIO and debug.logger('handle_write: ignoring socket error %s' % exc)
+            if exc.args[0] in SOCK_ERRORS:
+                debug.logger & debug.FLAG_IO and debug.logger('handle_write: ignoring socket error %s' % exc)
             else:
                 raise error.CarrierError('sendto() failed for %s: %s' % (transportAddress, exc))
 
@@ -161,7 +161,7 @@ class DgramSocketTransport(AbstractSocketTransport):
         try:
             incomingMessage, transportAddress = self._recvfrom(self.socket, 65535)
             transportAddress = self.normalizeAddress(transportAddress)
-            debug.logger & debug.flagIO and debug.logger(
+            debug.logger & debug.FLAG_IO 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()
@@ -170,9 +170,9 @@ class DgramSocketTransport(AbstractSocketTransport):
                 self._cbFun(self, transportAddress, incomingMessage)
                 return
         except socket.error as exc:
-            if exc.args[0] in sockErrors:
-                debug.logger & debug.flagIO and debug.logger('handle_read: known socket error %s' % exc)
-                sockErrors[exc.args[0]] and self.handle_close()
+            if exc.args[0] in SOCK_ERRORS:
+                debug.logger & debug.FLAG_IO and debug.logger('handle_read: known socket error %s' % exc)
+                SOCK_ERRORS[exc.args[0]] and self.handle_close()
                 return
             else:
                 raise error.CarrierError('recvfrom() failed: %s' % exc)
diff --git a/pysnmp/carrier/asyncore/dgram/udp.py b/pysnmp/carrier/asyncore/dgram/udp.py
index 08ae5ceb..60bc32a9 100644
--- a/pysnmp/carrier/asyncore/dgram/udp.py
+++ b/pysnmp/carrier/asyncore/dgram/udp.py
@@ -8,7 +8,7 @@ from socket import AF_INET
 from pysnmp.carrier.base import AbstractTransportAddress
 from pysnmp.carrier.asyncore.dgram.base import DgramSocketTransport
 
-domainName = snmpUDPDomain = (1, 3, 6, 1, 6, 1, 1)
+DOMAIN_NAME = SNMP_UDP_DOMAIN = (1, 3, 6, 1, 6, 1, 1)
 
 
 class UdpTransportAddress(tuple, AbstractTransportAddress):
@@ -16,8 +16,8 @@ class UdpTransportAddress(tuple, AbstractTransportAddress):
 
 
 class UdpSocketTransport(DgramSocketTransport):
-    sockFamily = AF_INET
-    addressType = UdpTransportAddress
+    SOCK_FAMILY = AF_INET
+    ADDRESS_TYPE = UdpTransportAddress
 
 
 UdpTransport = UdpSocketTransport
diff --git a/pysnmp/carrier/asyncore/dgram/udp6.py b/pysnmp/carrier/asyncore/dgram/udp6.py
index 900ef3c7..ee99674d 100644
--- a/pysnmp/carrier/asyncore/dgram/udp6.py
+++ b/pysnmp/carrier/asyncore/dgram/udp6.py
@@ -9,7 +9,7 @@ from pysnmp.carrier.base import AbstractTransportAddress
 from pysnmp.carrier.asyncore.dgram.base import DgramSocketTransport
 import socket
 
-domainName = snmpUDP6Domain = (1, 3, 6, 1, 2, 1, 100, 1, 2)
+DOMAIN_NAME = SNMP_UDP6_DOMAIN = (1, 3, 6, 1, 2, 1, 100, 1, 2)
 
 
 class Udp6TransportAddress(tuple, AbstractTransportAddress):
@@ -17,8 +17,8 @@ class Udp6TransportAddress(tuple, AbstractTransportAddress):
 
 
 class Udp6SocketTransport(DgramSocketTransport):
-    sockFamily = socket.has_ipv6 and socket.AF_INET6 or None
-    addressType = Udp6TransportAddress
+    SOCK_FAMILY = socket.has_ipv6 and socket.AF_INET6 or None
+    ADDRESS_TYPE = Udp6TransportAddress
 
     def normalizeAddress(self, transportAddress):
         if '%' in transportAddress[0]:  # strip zone ID
diff --git a/pysnmp/carrier/asyncore/dgram/unix.py b/pysnmp/carrier/asyncore/dgram/unix.py
index 15f68b2b..486c84f8 100644
--- a/pysnmp/carrier/asyncore/dgram/unix.py
+++ b/pysnmp/carrier/asyncore/dgram/unix.py
@@ -14,7 +14,7 @@ except ImportError:
 from pysnmp.carrier.base import AbstractTransportAddress
 from pysnmp.carrier.asyncore.dgram.base import DgramSocketTransport
 
-domainName = snmpLocalDomain = (1, 3, 6, 1, 2, 1, 100, 1, 13)
+DOMAIN_NAME = SNMP_LOCAL_DOMAIN = (1, 3, 6, 1, 2, 1, 100, 1, 13)
 
 random.seed()
 
@@ -24,8 +24,8 @@ class UnixTransportAddress(str, AbstractTransportAddress):
 
 
 class UnixSocketTransport(DgramSocketTransport):
-    sockFamily = AF_UNIX
-    addressType = UnixTransportAddress
+    SOCK_FAMILY = AF_UNIX
+    ADDRESS_TYPE = UnixTransportAddress
     _iface = ''
 
     def openClientMode(self, iface=None):
diff --git a/pysnmp/carrier/asyncore/dispatch.py b/pysnmp/carrier/asyncore/dispatch.py
index 221c596c..3517bdff 100644
--- a/pysnmp/carrier/asyncore/dispatch.py
+++ b/pysnmp/carrier/asyncore/dispatch.py
@@ -35,8 +35,7 @@ class AsyncoreDispatcher(AbstractTransportDispatcher):
     def transportsAreWorking(self):
         for transport in self.__sockMap.values():
             if transport.writable():
-                return 1
-        return 0
+                return True
 
     def runDispatcher(self, timeout=0.0):
         while self.jobsArePending() or self.transportsAreWorking():
@@ -45,6 +44,7 @@ class AsyncoreDispatcher(AbstractTransportDispatcher):
                      use_poll=True, map=self.__sockMap, count=1)
             except KeyboardInterrupt:
                 raise
-            except:
+
+            except Exception:
                 raise PySnmpError('poll error: %s' % ';'.join(format_exception(*exc_info())))
             self.handleTimerTick(time())
diff --git a/pysnmp/carrier/base.py b/pysnmp/carrier/base.py
index 017a1520..12dfc86b 100644
--- a/pysnmp/carrier/base.py
+++ b/pysnmp/carrier/base.py
@@ -211,13 +211,13 @@ class AbstractTransportAddress(object):
 
 
 class AbstractTransport(object):
-    protoTransportDispatcher = None
-    addressType = AbstractTransportAddress
+    PROTO_TRANSPORT_DISPATCHER = None
+    ADDRESS_TYPE = AbstractTransportAddress
     _cbFun = None
 
     @classmethod
     def isCompatibleWithDispatcher(cls, transportDispatcher):
-        return isinstance(transportDispatcher, cls.protoTransportDispatcher)
+        return isinstance(transportDispatcher, cls.PROTO_TRANSPORT_DISPATCHER)
 
     def registerCbFun(self, cbFun):
         if self._cbFun:
diff --git a/pysnmp/carrier/sockfix.py b/pysnmp/carrier/sockfix.py
index fab6d1aa..edfc1631 100644
--- a/pysnmp/carrier/sockfix.py
+++ b/pysnmp/carrier/sockfix.py
@@ -22,7 +22,7 @@ for symbol, value in SYMBOLS.items():
     if not hasattr(socket, symbol):
         setattr(socket, symbol, value)
 
-        debug.logger & debug.flagIO and debug.logger(
+        debug.logger & debug.FLAG_IO and debug.logger(
             'WARNING: the socket module on this platform misses option %s. '
             'Assuming its value is %d.' % (symbol, value)
         )
diff --git a/pysnmp/carrier/sockmsg.py b/pysnmp/carrier/sockmsg.py
index 4ff55a91..deab4b6d 100644
--- a/pysnmp/carrier/sockmsg.py
+++ b/pysnmp/carrier/sockmsg.py
@@ -27,6 +27,7 @@ if sys.version_info[:2] < (3, 3):
 
     def getSendTo(addressType):
         raise error.CarrierError('sendmsg()/recvmsg() interface is not supported by this OS and/or Python version')
+
 else:
     import ctypes
     import ipaddress
@@ -91,7 +92,7 @@ else:
                     _to = (str(addr), s.getsockname()[1])
                     break
 
-            debug.logger & debug.flagIO and debug.logger(
+            debug.logger & debug.FLAG_IO and debug.logger(
                 'recvfrom: received %d octets from %s to %s; '
                 'iov blob %r' % (len(data), _from, _to, ancdata))
 
@@ -120,7 +121,7 @@ else:
                 _f.ipi6_addr = in6_addr.from_buffer_copy(addr.packed)
                 ancdata = [(socket.SOL_IPV6, socket.IPV6_PKTINFO, memoryview(_f).tobytes())]
 
-            debug.logger & debug.flagIO and debug.logger(
+            debug.logger & debug.FLAG_IO and debug.logger(
                 'sendto: sending %d octets to %s; address %r; '
                 'iov blob %r' % (len(_data), _to, addr, ancdata))
 
diff --git a/pysnmp/carrier/twisted/base.py b/pysnmp/carrier/twisted/base.py
index d8b75bc7..91883d7d 100644
--- a/pysnmp/carrier/twisted/base.py
+++ b/pysnmp/carrier/twisted/base.py
@@ -17,7 +17,7 @@ from pysnmp.carrier.base import AbstractTransport
 
 
 class AbstractTwistedTransport(AbstractTransport):
-    protoTransportDispatcher = TwistedDispatcher
+    PROTO_TRANSPORT_DISPATCHER = TwistedDispatcher
 
     def __init__(self, sock=None, sockMap=None):
         self._writeQ = []
diff --git a/pysnmp/carrier/twisted/dgram/base.py b/pysnmp/carrier/twisted/dgram/base.py
index 4386b702..42eb7c04 100644
--- a/pysnmp/carrier/twisted/dgram/base.py
+++ b/pysnmp/carrier/twisted/dgram/base.py
@@ -26,20 +26,20 @@ class DgramTwistedTransport(DatagramProtocol, AbstractTwistedTransport):
             reactor.callLater(0, self._cbFun, self, transportAddress, datagram)
 
     def startProtocol(self):
-        debug.logger & debug.flagIO and debug.logger('startProtocol: invoked')
+        debug.logger & debug.FLAG_IO and debug.logger('startProtocol: invoked')
         while self._writeQ:
             outgoingMessage, transportAddress = self._writeQ.pop(0)
-            debug.logger & debug.flagIO and debug.logger('startProtocol: transportAddress %r outgoingMessage %s' % (transportAddress, debug.hexdump(outgoingMessage)))
+            debug.logger & debug.FLAG_IO and debug.logger('startProtocol: transportAddress %r outgoingMessage %s' % (transportAddress, debug.hexdump(outgoingMessage)))
             try:
                 self.transport.write(outgoingMessage, transportAddress)
             except Exception as exc:
                 raise error.CarrierError('Twisted exception: %s' % exc)
 
     def stopProtocol(self):
-        debug.logger & debug.flagIO and debug.logger('stopProtocol: invoked')
+        debug.logger & debug.FLAG_IO and debug.logger('stopProtocol: invoked')
 
     def sendMessage(self, outgoingMessage, transportAddress):
-        debug.logger & debug.flagIO and debug.logger('startProtocol: %s transportAddress %r outgoingMessage %s' % ((self.transport is None and "queuing" or "sending"), transportAddress, debug.hexdump(outgoingMessage)))
+        debug.logger & debug.FLAG_IO and debug.logger('startProtocol: %s transportAddress %r outgoingMessage %s' % ((self.transport is None and "queuing" or "sending"), transportAddress, debug.hexdump(outgoingMessage)))
         if self.transport is None:
             self._writeQ.append((outgoingMessage, transportAddress))
         else:
diff --git a/pysnmp/carrier/twisted/dgram/udp.py b/pysnmp/carrier/twisted/dgram/udp.py
index bdb93cdd..eb47bb24 100644
--- a/pysnmp/carrier/twisted/dgram/udp.py
+++ b/pysnmp/carrier/twisted/dgram/udp.py
@@ -10,7 +10,7 @@ from pysnmp.carrier.base import AbstractTransportAddress
 from pysnmp.carrier.twisted.dgram.base import DgramTwistedTransport
 from pysnmp.carrier import error
 
-domainName = snmpUDPDomain = (1, 3, 6, 1, 6, 1, 1)
+DOMAIN_NAME = SNMP_UDP_DOMAIN = (1, 3, 6, 1, 6, 1, 1)
 
 
 class UdpTransportAddress(tuple, AbstractTransportAddress):
@@ -18,7 +18,7 @@ class UdpTransportAddress(tuple, AbstractTransportAddress):
 
 
 class UdpTwistedTransport(DgramTwistedTransport):
-    addressType = UdpTransportAddress
+    ADDRESS_TYPE = UdpTransportAddress
     _lport = None
 
     # AbstractTwistedTransport API
diff --git a/pysnmp/carrier/twisted/dgram/unix.py b/pysnmp/carrier/twisted/dgram/unix.py
index fe9c459b..24fdc5c7 100644
--- a/pysnmp/carrier/twisted/dgram/unix.py
+++ b/pysnmp/carrier/twisted/dgram/unix.py
@@ -10,13 +10,15 @@ from pysnmp.carrier.base import AbstractTransportAddress
 from pysnmp.carrier.twisted.dgram.base import DgramTwistedTransport
 from pysnmp.carrier import error
 
-domainName = snmpLocalDomain = (1, 3, 6, 1, 2, 1, 100, 1, 13)
+DOMAIN_NAME = SNMP_LOCAL_DOMAIN = (1, 3, 6, 1, 2, 1, 100, 1, 13)
+
 
 class UnixTransportAddress(str, AbstractTransportAddress):
     pass
 
+
 class UnixTwistedTransport(DgramTwistedTransport):
-    addressType = UnixTransportAddress
+    ADDRESS_TYPE = UnixTransportAddress
     _lport = None
 
     # AbstractTwistedTransport API
@@ -43,4 +45,5 @@ class UnixTwistedTransport(DgramTwistedTransport):
                 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 def16f6f..cacc20b4 100644
--- a/pysnmp/carrier/twisted/dispatch.py
+++ b/pysnmp/carrier/twisted/dispatch.py
@@ -34,9 +34,11 @@ class TwistedDispatcher(AbstractTransportDispatcher):
         if not reactor.running:
             try:
                 reactor.run()
+
             except KeyboardInterrupt:
                 raise
-            except:
+
+            except Exception:
                 raise PySnmpError('reactor error: %s' % ';'.join(traceback.format_exception(*sys.exc_info())))
 
     # jobstarted/jobfinished might be okay as-is