Using nltk with Python 3 (6)

And chapter six it is.

The Bayes Classifier raises an error, but it does so as well in Python 2.7. Maybe the book is wrong here or uses a dated version? I will step over it for now, as the classifiers will be looked upon more closely later on, when the official nltk book is done. There are far more interestings bookts concerning nltk out there.