CodecInfo objects are supposed to have 'encoder' and 'decoder' 
attributes as per http://www.python.org/doc/2.5.2/lib/module-codecs.html 
(naturally, this applies to 2.5.* as well). However, at least the 
CodecInfo object for 'string_escape' names these attributes 'encode' and 
'decode'.

>>> import codecs
>>> dir(codecs.lookup('string_escape'))
['__add__', '__class__', '__contains__', '__delattr__', '__dict__', 
'__doc__', '__eq__', '__ge__', '__getattribute__', '__getitem__', 
'__getnewargs__', '__getslice__', '__gt__', '__hash__', '__init__', 
'__iter__', '__le__', '__len__', '__lt__', '__module__', '__mul__', 
'__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', 
'__rmul__', '__setattr__', '__str__', 'decode', 'encode', 
'incrementaldecoder', 'incrementalencoder', 'name', 'streamreader', 
'streamwriter']