code: def _retrieve_tag(self, text):
          
          if self.tagger == 'tag_ngram_123_backoff':  # Data format: Perseus Style (see https://github.com/cltk/latin_treebank_perseus)
              tags = POSTag('latin').tag_ngram_123_backoff(text.lower())
              return [(tag[0], tag[1]) for tag in tags]
          elif self.tagger == 'tag_tnt':
              tags = POSTag('latin').tag_tnt(text.lower())
              return [(tag[0], tag[1]) for tag in tags]
          elif self.tagger == 'tag_crf':
              tags = POSTag('latin').tag_crf(text.lower())
              return [(tag[0], tag[1]) for tag in tags]
docs: Tag text with chosen tagger and clean tags.
  
          Tag format: [('word', 'tag')]
  
          :param text: string
          :return: list of tuples, with each tuple containing the word and its pos tag
          :rtype : list