code: def save(self, *args, **kwargs):
          
          rerank = kwargs.pop('rerank', True)
          if rerank:
              if not self.id:
                  self._process_new_rank_obj()
              elif self.rank == self._rank_at_load:
                  # nothing changed
                  pass
              else:
                  self._process_moved_rank_obj()
  
          super(RankedModel, self).save(*args, **kwargs)
docs: Overridden method that handles that re-ranking of objects and the
          integrity of the ``rank`` field.
  
          :param rerank:
              Added parameter, if True will rerank other objects based on the
              change in this save.  Defaults to True.