code: def tag_labels(self):
          
          if not self.is_tagged(ANALYSIS):
              self.tag_analysis()
          if self.__ner_tagger is None:
              self.__ner_tagger = load_default_ner_tagger()
          self.__ner_tagger.tag_document(self)
          return self
docs: Tag named entity labels in the ``words`` layer.