code: def train(self, *args, **kwargs):
          
          self.classifier = self.nltk_class.train(self.positive_features,
                                                  self.unlabeled_features,
                                                  self.positive_prob_prior)
          return self.classifier
docs: Train the classifier with a labeled and unlabeled feature sets and
          return the classifier. Takes the same arguments as the wrapped NLTK
          class. This method is implicitly called when calling ``classify`` or
          ``accuracy`` methods and is included only to allow passing in arguments
          to the ``train`` method of the wrapped NLTK class.
  
          :rtype: A classifier