Remove a few custom exception types.

The following custom exceptions are replaced with ValueError:
* Crypto.Util.PaddingError
* Crypto.PublicKey.KeyFormatError

The custom Crypto.Util.asn1.NoDerElementError is now private to the
module.

Some white spaces have been removed.

5 files changed, 84 insertions, 90 deletions

diff --git a/lib/Crypto/PublicKey/DSA.py b/lib/Crypto/PublicKey/DSA.py
index 1818def..69f7f04 100644
--- a/lib/Crypto/PublicKey/DSA.py
+++ b/lib/Crypto/PublicKey/DSA.py
@@ -99,7 +99,7 @@ from Crypto.Util.py3compat import *
 from Crypto import Random
 from Crypto.IO import PKCS8, PEM
 from Crypto.Util.number import bytes_to_long, long_to_bytes
-from Crypto.PublicKey import _DSA, _slowmath, pubkey, KeyFormatError
+from Crypto.PublicKey import _DSA, _slowmath, pubkey
 from Crypto.Util.asn1 import DerObject, DerSequence,\
         DerInteger, DerObjectId, DerBitString, newDerSequence, newDerBitString
 
@@ -496,7 +496,7 @@ class DSAImplementation(object):
         :Raise ValueError:
             When **bits** is too little, too big, or not a multiple of 64.
         """
- 
+
         # Check against FIPS 186-2, which says that the size of the prime p
         # must be a multiple of 64 bits between 512 and 1024
         for i in (0, 1, 2, 3, 4, 5, 6, 7, 8):
@@ -596,7 +596,7 @@ class DSAImplementation(object):
         except (ValueError, EOFError):
             pass
 
-        raise KeyFormatError("DSA key format is not supported")
+        raise ValueError("DSA key format is not supported")
 
     def importKey(self, extern_key, passphrase=None):
         """Import a DSA key (public or private).
@@ -626,7 +626,7 @@ class DSAImplementation(object):
             from which the decryption key is derived.
 
         :Return: A DSA key object (`_DSAobj`).
-        :Raise KeyFormatError:
+        :Raise ValueError:
             When the given key cannot be parsed (possibly because
             the pass phrase is wrong).
 
@@ -663,7 +663,7 @@ class DSAImplementation(object):
             # This is probably a DER encoded key
             return self._importKeyDER(extern_key, passphrase)
 
-        raise KeyFormatError("DSA key format is not supported")
+        raise ValueError("DSA key format is not supported")
 
 #: `Object ID`_ for a DSA key.
 #:
diff --git a/lib/Crypto/PublicKey/__init__.py b/lib/Crypto/PublicKey/__init__.py
index df60c25..503809f 100644
--- a/lib/Crypto/PublicKey/__init__.py
+++ b/lib/Crypto/PublicKey/__init__.py
@@ -36,9 +36,6 @@ Crypto.PublicKey.RSA      (Signing, encryption, and blinding)
 :undocumented: _DSA, _RSA, _fastmath, _slowmath, pubkey
 """
 
-class KeyFormatError(ValueError):
-    pass
-
 __all__ = ['RSA', 'DSA', 'ElGamal']
 __revision__ = "$Id$"
 
diff --git a/lib/Crypto/SelfTest/PublicKey/test_import_DSA.py b/lib/Crypto/SelfTest/PublicKey/test_import_DSA.py
index 1cb6837..82e1ad8 100644
--- a/lib/Crypto/SelfTest/PublicKey/test_import_DSA.py
+++ b/lib/Crypto/SelfTest/PublicKey/test_import_DSA.py
@@ -22,7 +22,7 @@
 
 import unittest
 
-from Crypto.PublicKey import DSA, KeyFormatError
+from Crypto.PublicKey import DSA
 from Crypto.SelfTest.st_common import *
 from Crypto.Util.py3compat import *
 
@@ -73,7 +73,7 @@ class ImportKeyTests(unittest.TestCase):
         self.assertEqual(self.g, key_obj.key.g)
 
     def testExportKey1(self):
-        tup = (self.y, self.g, self.p, self.q) 
+        tup = (self.y, self.g, self.p, self.q)
         key = self.dsa.construct(tup)
         encoded = key.exportKey('DER')
         self.assertEqual(self.der_public, encoded)
@@ -103,7 +103,7 @@ tPG+TJKpGYb7pVk=
             self.assertEqual(self.g, key_obj.key.g)
 
     def testExportKey2(self):
-        tup = (self.y, self.g, self.p, self.q) 
+        tup = (self.y, self.g, self.p, self.q)
         key = self.dsa.construct(tup)
         encoded = key.exportKey('PEM')
         self.assertEqual(self.pem_public, encoded)
@@ -124,7 +124,7 @@ tPG+TJKpGYb7pVk=
     'a40ed9c2630c2fa4cdbf838539deb9a29f919085f2046369f627ca84b2cb1e2c'+\
     '7940564b670f963ab1164d4e2ca2bf6ffd39f12f548928bf4d2d1b5e6980b4f1'+\
     'be4c92a91986fba55902145ebd9a3f0b82069d98420986b314215025756065'
- 
+
     def testImportKey3(self):
         key_obj = self.dsa.importKey(self.der_private)
         self.failUnless(key_obj.has_private())
@@ -135,11 +135,11 @@ tPG+TJKpGYb7pVk=
         self.assertEqual(self.x, key_obj.key.x)
 
     def testExportKey3(self):
-        tup = (self.y, self.g, self.p, self.q, self.x) 
+        tup = (self.y, self.g, self.p, self.q, self.x)
         key = self.dsa.construct(tup)
         encoded = key.exportKey('DER', pkcs8=False)
         self.assertEqual(self.der_private, encoded)
- 
+
     # 4.
     pem_private="""\
 -----BEGIN DSA PRIVATE KEY-----
@@ -166,11 +166,11 @@ ggadmEIJhrMUIVAldWBl
             self.assertEqual(self.x, key_obj.key.x)
 
     def testExportKey4(self):
-        tup = (self.y, self.g, self.p, self.q, self.x) 
+        tup = (self.y, self.g, self.p, self.q, self.x)
         key = self.dsa.construct(tup)
         encoded = key.exportKey('PEM', pkcs8=False)
         self.assertEqual(self.pem_private, encoded)
- 
+
     # 5. PKCS8 (unencrypted)
     der_pkcs8=\
     '3082014a0201003082012b06072a8648ce3804013082011e02818100e756ee17'+\
@@ -183,8 +183,8 @@ ggadmEIJhrMUIVAldWBl
     'f444f34b82e3554d0b90a778faaf1306f025dae6a3e36c7f93dd5bac4052b923'+\
     '70040aca70b8d5820599711900efbc961812c355dd9beffe0981da85c5548074'+\
     'b41c56ae43fd300d89262e4efd89943f99a651b03888041602145ebd9a3f0b82'+\
-    '069d98420986b314215025756065' 
- 
+    '069d98420986b314215025756065'
+
     def testImportKey5(self):
         key_obj = self.dsa.importKey(self.der_pkcs8)
         self.failUnless(key_obj.has_private())
@@ -195,13 +195,13 @@ ggadmEIJhrMUIVAldWBl
         self.assertEqual(self.x, key_obj.key.x)
 
     def testExportKey5(self):
-        tup = (self.y, self.g, self.p, self.q, self.x) 
+        tup = (self.y, self.g, self.p, self.q, self.x)
         key = self.dsa.construct(tup)
         encoded = key.exportKey('DER')
         self.assertEqual(self.der_pkcs8, encoded)
         encoded = key.exportKey('DER', pkcs8=True)
         self.assertEqual(self.der_pkcs8, encoded)
- 
+
     # 6.
     pem_pkcs8="""\
 -----BEGIN PRIVATE KEY-----
@@ -213,7 +213,7 @@ fq6uNxjcLv77RSgpk6xnSdyDwiPYwYhyljFrOwtURmz0RPNLguNVTQuQp3j6rxMG
 8CXa5qPjbH+T3VusQFK5I3AECspwuNWCBZlxGQDvvJYYEsNV3Zvv/gmB2oXFVIB0
 tBxWrkP9MA2JJi5O/YmUP5mmUbA4iAQWAhRevZo/C4IGnZhCCYazFCFQJXVgZQ==
 -----END PRIVATE KEY-----"""
-  
+
     def testImportKey6(self):
         for pem in (self.pem_pkcs8, tostr(self.pem_pkcs8)):
             key_obj = self.dsa.importKey(pem)
@@ -225,16 +225,16 @@ tBxWrkP9MA2JJi5O/YmUP5mmUbA4iAQWAhRevZo/C4IGnZhCCYazFCFQJXVgZQ==
             self.assertEqual(self.x, key_obj.key.x)
 
     def testExportKey6(self):
-        tup = (self.y, self.g, self.p, self.q, self.x) 
+        tup = (self.y, self.g, self.p, self.q, self.x)
         key = self.dsa.construct(tup)
         encoded = key.exportKey('PEM')
         self.assertEqual(self.pem_pkcs8, encoded)
         encoded = key.exportKey('PEM', pkcs8=True)
         self.assertEqual(self.pem_pkcs8, encoded)
- 
+
     # 7. OpenSSH/RFC4253
     ssh_pub="""ssh-dss 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"""
- 
+
     def testImportKey7(self):
         for ssh in (self.ssh_pub, tostr(self.ssh_pub)):
             key_obj = self.dsa.importKey(ssh)
@@ -245,11 +245,11 @@ tBxWrkP9MA2JJi5O/YmUP5mmUbA4iAQWAhRevZo/C4IGnZhCCYazFCFQJXVgZQ==
             self.assertEqual(self.g, key_obj.key.g)
 
     def testExportKey7(self):
-        tup = (self.y, self.g, self.p, self.q) 
+        tup = (self.y, self.g, self.p, self.q)
         key = self.dsa.construct(tup)
         encoded = key.exportKey('OpenSSH')
         self.assertEqual(self.ssh_pub, encoded)
- 
+
     # 8. Encrypted OpenSSL/OpenSSH
     pem_private_encrypted="""\
 -----BEGIN DSA PRIVATE KEY-----
@@ -279,7 +279,7 @@ xVJtxaV37m3aXxtCsPnbBg==
             self.assertEqual(self.x, key_obj.key.x)
 
     def testExportKey8(self):
-        tup = (self.y, self.g, self.p, self.q, self.x) 
+        tup = (self.y, self.g, self.p, self.q, self.x)
         key = self.dsa.construct(tup)
         encoded = key.exportKey('PEM', pkcs8=False, passphrase="PWDTEST")
         key = self.dsa.importKey(encoded, "PWDTEST")
@@ -288,7 +288,7 @@ xVJtxaV37m3aXxtCsPnbBg==
         self.assertEqual(self.q, key.key.q)
         self.assertEqual(self.g, key.key.g)
         self.assertEqual(self.x, key.key.x)
- 
+
     # 9. Encrypted PKCS8
     # pbeWithMD5AndDES-CBC
     pem_pkcs8_encrypted="""\
@@ -343,7 +343,7 @@ eZ4k+NQDbEL8GiHmFxzDWQAuPPZKJWEEEV2p/To+WOh+kSDHQw==
         self.assertEqual(self.x, key_obj.key.x)
 
     def testExportKey10(self):
-        tup = (self.y, self.g, self.p, self.q, self.x) 
+        tup = (self.y, self.g, self.p, self.q, self.x)
         key = self.dsa.construct(tup)
         randfunc = BytesIO(unhexlify(b("27A1C66C42AFEECE") + b("D725BF1B6B8239F4"))).read
         key._randfunc = randfunc
@@ -353,10 +353,10 @@ eZ4k+NQDbEL8GiHmFxzDWQAuPPZKJWEEEV2p/To+WOh+kSDHQw==
     # ----
 
     def testImportError1(self):
-        self.assertRaises(KeyFormatError, self.dsa.importKey, self.der_pkcs8_encrypted, "wrongpwd")
+        self.assertRaises(ValueError, self.dsa.importKey, self.der_pkcs8_encrypted, "wrongpwd")
 
     def testExportError2(self):
-        tup = (self.y, self.g, self.p, self.q, self.x) 
+        tup = (self.y, self.g, self.p, self.q, self.x)
         key = self.dsa.construct(tup)
         self.assertRaises(ValueError, key.exportKey, 'DER', pkcs8=False, passphrase="PWDTEST")
 
diff --git a/lib/Crypto/Util/Padding.py b/lib/Crypto/Util/Padding.py
index b8498a3..e05b79a 100644
--- a/lib/Crypto/Util/Padding.py
+++ b/lib/Crypto/Util/Padding.py
@@ -27,17 +27,14 @@ This module provides minimal support for adding and removing standard padding
 from data.
 """
 
-__all__ = [ 'PaddingError', 'pad', 'unpad' ]
+__all__ = [ 'ValueError', 'pad', 'unpad' ]
 
 from Crypto.Util.py3compat import *
 
-class PaddingError(ValueError):
-    """Exception raised when padding is incorrect and cannot be removed."""
-    pass
 
 def pad(data_to_pad, block_size, style='pkcs7'):
     """Apply standard padding.
-    
+
     :Parameters:
       data_to_pad : byte string
         The data that needs to be padded.
@@ -63,7 +60,7 @@ def pad(data_to_pad, block_size, style='pkcs7'):
 
 def unpad(padded_data, block_size, style='pkcs7'):
     """Remove standard padding.
-   
+
     :Parameters:
       padded_data : byte string
         A piece of data with padding that needs to be stripped.
@@ -74,29 +71,29 @@ def unpad(padded_data, block_size, style='pkcs7'):
         Padding algorithm. It can be *'pkcs7'* (default), *'iso7816'* or *'x923'*.
     :Return:
         Data without padding.
-    :Raises PaddingError:
+    :Raises ValueError:
         if the padding is incorrect.
     """
 
     pdata_len = len(padded_data)
     if pdata_len % block_size:
-        raise PaddingError("Input data is not padded")
+        raise ValueError("Input data is not padded")
     if style in ('pkcs7', 'x923'):
         padding_len = bord(padded_data[-1])
         if padding_len<1 or padding_len>min(block_size, pdata_len):
-            raise PaddingError("Padding is incorrect.")
+            raise ValueError("Padding is incorrect.")
         if style == 'pkcs7':
             if padded_data[-padding_len:]!=bchr(padding_len)*padding_len:
-                raise PaddingError("PKCS#7 padding is incorrect.")
+                raise ValueError("PKCS#7 padding is incorrect.")
         else:
             if padded_data[-padding_len:-1]!=bchr(0)*(padding_len-1):
-                raise PaddingError("ANSI X.923 padding is incorrect.")
+                raise ValueError("ANSI X.923 padding is incorrect.")
     elif style == 'iso7816':
         padding_len = pdata_len - padded_data.rfind(bchr(128))
         if padding_len<1 or padding_len>min(block_size, pdata_len):
-            raise PaddingError("Padding is incorrect.")
+            raise ValueError("Padding is incorrect.")
         if padding_len>1 and padded_data[1-padding_len:]!=bchr(0)*(padding_len-1):
-            raise PaddingError("ISO 7816-4 padding is incorrect.")
+            raise ValueError("ISO 7816-4 padding is incorrect.")
     else:
         raise ValueError("Unknown padding style")
     return padded_data[:-padding_len]
diff --git a/lib/Crypto/Util/asn1.py b/lib/Crypto/Util/asn1.py
index 0e471a3..4c0ca37 100644
--- a/lib/Crypto/Util/asn1.py
+++ b/lib/Crypto/Util/asn1.py
@@ -76,7 +76,7 @@ class BytesIO_EOF(BytesIO):
     def read_byte(self):
         return self.read(1)[0]
 
-class NoDerElementError(EOFError):
+class _NoDerElementError(EOFError):
     pass
 
 class DerObject(object):
@@ -106,7 +106,7 @@ class DerObject(object):
                     True when the ASN.1 type is *constructed*.
                     False when it is *primitive*.
                 """
-               
+
                 if asn1Id==None:
                     self._idOctet = None
                     return
@@ -118,7 +118,7 @@ class DerObject(object):
                     # * bit 5 is set if the type is 'construted'
                     #   and unset if 'primitive'
                     # * bits 7-6 depend on the encoding class
-                    # 
+                    #
                     # Class        | Bit 7, Bit 6
                     # universal    |   0      0
                     # application  |   0      1
@@ -146,7 +146,7 @@ class DerObject(object):
 
         def _lengthOctets(self):
                 """Build length octets according to the current object's payload.
-                
+
                 Return a byte string that encodes the payload length (in
                 bytes) in a format suitable for DER length octets (L).
                 """
@@ -182,7 +182,7 @@ class DerObject(object):
                 :Parameters:
                   derEle : byte string
                     A complete DER element.
-                
+
                 :Raise ValueError:
                   In case of parsing errors.
                 :Raise EOFError:
@@ -197,14 +197,14 @@ class DerObject(object):
                     raise ValueError("Unexpected extra data after the DER structure")
                 except EOFError:
                     pass
-        
+
         def _decodeFromStream(self, s):
                 """Decode a complete DER element from a file."""
-                
+
                 try:
                     idOctet = bord(s.read_byte())
                 except EOFError:
-                    raise NoDerElementError
+                    raise _NoDerElementError
                 if self._idOctet != None:
                     if idOctet != self._idOctet:
                         raise ValueError("Unexpected DER tag")
@@ -215,7 +215,7 @@ class DerObject(object):
 
 class DerInteger(DerObject):
         """Class to model a DER INTEGER.
-        
+
         An example of encoding is:
 
           >>> from Crypto.Util.asn1 import DerInteger
@@ -275,7 +275,7 @@ class DerInteger(DerObject):
                 :Parameters:
                   derEle : byte string
                     A complete INTEGER DER element.
-                
+
                 :Raise ValueError:
                   In case of parsing errors.
                 :Raise EOFError:
@@ -285,10 +285,10 @@ class DerInteger(DerObject):
 
         def _decodeFromStream(self, s):
                 """Decode a complete DER INTEGER from a file."""
- 
+
                 # Fill up self.payload
                 DerObject._decodeFromStream(self, s)
-                
+
                 # Derive self.value from self.payload
                 self.value = 0L
                 bits = 1
@@ -311,7 +311,7 @@ class DerSequence(DerObject):
         This object behaves like a dynamic Python sequence.
 
         Sub-elements that are INTEGERs behave like Python integers.
-        
+
         Any other sub-element is a binary string encoded as a complete DER
         sub-element (TLV).
 
@@ -345,12 +345,12 @@ class DerSequence(DerObject):
           3
           4
           [4L, 9L, b'\x07\x01\x02']
- 
+
         """
 
         def __init__(self, startSeq=None, implicit=None):
                 """Initialize the DER object as a SEQUENCE.
-                
+
                 :Parameters:
                   startSeq : Python sequence
                     A sequence whose element are either integers or
@@ -393,7 +393,7 @@ class DerSequence(DerObject):
         def hasInts(self, onlyNonNegative=True):
                 """Return the number of items in this sequence that are
                 integers.
-                
+
                 :Parameters:
                   onlyNonNegative : boolean
                     If True, negative integers are not counted in.
@@ -411,14 +411,14 @@ class DerSequence(DerObject):
 
                 :Parameters:
                   onlyNonNegative : boolean
-                    If True, the presence of negative integers 
+                    If True, the presence of negative integers
                     causes the method to return False."""
                 return self._seq and self.hasInts(onlyNonNegative)==len(self._seq)
- 
+
         def encode(self):
                 """Return this DER SEQUENCE, fully encoded as a
                 binary string.
-                
+
                 :Raises ValueError:
                   If some elements in the sequence are neither integers
                   nor byte strings.
@@ -441,7 +441,7 @@ class DerSequence(DerObject):
                 :Parameters:
                   derEle : byte string
                     A complete SEQUENCE DER element.
-                
+
                 :Raise ValueError:
                   In case of parsing errors.
                 :Raise EOFError:
@@ -454,9 +454,9 @@ class DerSequence(DerObject):
 
         def _decodeFromStream(self, s):
                 """Decode a complete DER SEQUENCE from a file."""
- 
+
                 self._seq = []
-               
+
                 # Fill up self.payload
                 DerObject._decodeFromStream(self, s)
 
@@ -467,7 +467,7 @@ class DerSequence(DerObject):
                         p.setRecord(True)
                         der = DerObject()
                         der._decodeFromStream(p)
-         
+
                         # Parse INTEGERs differently
                         if der._idOctet != 0x02:
                             self._seq.append(p._recording)
@@ -475,8 +475,8 @@ class DerSequence(DerObject):
                             derInt = DerInteger()
                             derInt.decode(p._recording)
                             self._seq.append(derInt.value)
-                
-                    except NoDerElementError:
+
+                    except _NoDerElementError:
                         break
                 # end
 
@@ -494,7 +494,7 @@ def newDerSequence(*der_objs):
 
 class DerOctetString(DerObject):
     """Class to model a DER OCTET STRING.
-    
+
     An example of encoding is:
 
     >>> from Crypto.Util.asn1 import DerOctetString
@@ -521,7 +521,7 @@ class DerOctetString(DerObject):
 
     def __init__(self, value=b(''), implicit=None):
         """Initialize the DER object as an OCTET STRING.
-        
+
         :Parameters:
           value : byte string
             The initial payload of the object.
@@ -530,7 +530,7 @@ class DerOctetString(DerObject):
           implicit : integer
             The IMPLICIT tag to use for the encoded object.
             It overrides the universal tag for OCTET STRING (4).
-        """ 
+        """
         DerObject.__init__(self, 0x04, value, implicit, False)
 
 def newDerOctetString(binstring):
@@ -553,7 +553,7 @@ class DerNull(DerObject):
 
 class DerObjectId(DerObject):
     """Class to model a DER OBJECT ID.
-    
+
     An example of encoding is:
 
     >>> from Crypto.Util.asn1 import DerObjectId
@@ -580,14 +580,14 @@ class DerObjectId(DerObject):
 
     def __init__(self, value='', implicit=None):
         """Initialize the DER object as an OBJECT ID.
-       
+
         :Parameters:
           value : string
             The initial Object Identifier (e.g. "1.2.0.0.6.2").
           implicit : integer
             The IMPLICIT tag to use for the encoded object.
             It overrides the universal tag for OBJECT ID (6).
-        """ 
+        """
         DerObject.__init__(self, 0x06, b(''), implicit, False)
         self.value = value #: The Object ID, a dot separated list of integers
 
@@ -623,7 +623,7 @@ class DerObjectId(DerObject):
         """
 
         DerObject.decode(self, derEle)
- 
+
     def _decodeFromStream(self, s):
         """Decode a complete DER OBJECT ID from a file."""
 
@@ -654,7 +654,7 @@ def newDerObjectId(dottedstring):
 
 class DerBitString(DerObject):
     """Class to model a DER BIT STRING.
-    
+
     An example of encoding is:
 
     >>> from Crypto.Util.asn1 import DerBitString
@@ -681,7 +681,7 @@ class DerBitString(DerObject):
 
     def __init__(self, value=b(''), implicit=None):
         """Initialize the DER object as a BIT STRING.
-        
+
         :Parameters:
           value : byte string
             The initial, packed bit string.
@@ -689,7 +689,7 @@ class DerBitString(DerObject):
           implicit : integer
             The IMPLICIT tag to use for the encoded object.
             It overrides the universal tag for OCTET STRING (3).
-        """ 
+        """
         DerObject.__init__(self, 0x03, b(''), implicit, False)
         self.value = value #: The bitstring value (packed)
 
@@ -700,7 +700,7 @@ class DerBitString(DerObject):
         # Add padding count byte
         self.payload = b('\x00') + self.value
         return DerObject.encode(self)
-    
+
     def decode(self, derEle):
         """Decode a complete DER BIT STRING, and re-initializes this
         object with it.
@@ -716,7 +716,7 @@ class DerBitString(DerObject):
         """
 
         DerObject.decode(self, derEle)
- 
+
     def _decodeFromStream(self, s):
         """Decode a complete DER BIT STRING DER from a file."""
 
@@ -725,7 +725,7 @@ class DerBitString(DerObject):
 
         if self.payload and bord(self.payload[0])!=0:
             raise ValueError("Not a valid BIT STRING")
-        
+
         # Fill-up self.value
         self.value = b('')
         # Remove padding count byte
@@ -744,7 +744,7 @@ def newDerBitString(binstring):
 
 class DerSetOf(DerObject):
     """Class to model a DER SET OF.
-    
+
     An example of encoding is:
 
     >>> from Crypto.Util.asn1 import DerBitString
@@ -771,14 +771,14 @@ class DerSetOf(DerObject):
 
     def __init__(self, startSet=None, implicit=None):
         """Initialize the DER object as a SET OF.
-        
+
         :Parameters:
           startSet : container
             The initial set of integers or DER encoded objects.
           implicit : integer
             The IMPLICIT tag to use for the encoded object.
             It overrides the universal tag for SET OF (17).
-        """ 
+        """
         DerObject.__init__(self, 0x11, b(''), implicit, True)
         self._seq = []
         self._elemOctet = None
@@ -830,14 +830,14 @@ class DerSetOf(DerObject):
         :Raise EOFError:
             If the DER element is too short.
         """
-        
+
         DerObject.decode(self, derEle)
 
     def _decodeFromStream(self, s):
         """Decode a complete DER SET OF from a file."""
 
         self._seq = []
-               
+
         # Fill up self.payload
         DerObject._decodeFromStream(self, s)
 
@@ -849,7 +849,7 @@ class DerSetOf(DerObject):
                 p.setRecord(True)
                 der = DerObject()
                 der._decodeFromStream(p)
-         
+
                 # Verify that all members are of the same type
                 if setIdOctet < 0:
                     setIdOctet = der._idOctet
@@ -864,8 +864,8 @@ class DerSetOf(DerObject):
                     derInt = DerInteger()
                     derInt.decode(p._recording)
                     self._seq.append(derInt.value)
-                
-            except NoDerElementError:
+
+            except _NoDerElementError:
                 break
         # end