code: def pos_tags(self):
      
      tagged_words = []
      for word,t in self.pos_tagger.annotate(self.words):
        word.pos_tag = t
        tagged_words.append((word, t))
      return tagged_words
docs: Returns an list of tuples of the form (word, POS tag).
      Example:
      ::
          [('At', 'ADP'), ('eight', 'NUM'), ("o'clock", 'NOUN'), ('on', 'ADP'),
          ('Thursday', 'NOUN'), ('morning', 'NOUN')]
      :rtype: list of tuples