nltk/nltk — pull request #193 by heatherleaf (2012-01-31 11:22:53+00:00)
Title: Make ConditionalProbDist a subclass of defaultdict

Now ConditionalProbDistI (and its subclasses) is a subclass of deafultdict.

There is no doctest that uses CPD, but I tried to create a HiddenMarkovModelTagger from CPD's and it worked fine.