Can you help me with the NameError?
Code:
def addExample(self, klass, words):
    """
     * TODO
     * Train your model on an example document with label klass ('pos' or 'neg') and
     * words, a list of strings.
     * You should store whatever data structures you use for your classifier 
     * in the NaiveBayes class.
     * Returns nothing
    """
...