code: def create_tags(self, entry):
          
          tag_list = [t.lower().strip() for t in entry.tag_string.split(',')]
          for t in tag_list:
              tag, created = self.get_or_create(name=t)
              entry.tags.add(tag)
docs: Inspects an ``Entry`` instance, and builds associates ``Tag``
          objects based on the values in the ``Entry``'s ``tag_string``.