<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def train(self, *args, **kwargs):
 """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 """

        self.classifier = self.nltk_class.train(self.positive_features,
                                                self.unlabeled_features,
                                                self.positive_prob_prior)
        return self.classifier