code: def shift_ordering_up(self, parent_id, position, db_session=None, *args, **kwargs):
          
          return self.service.shift_ordering_up(
              parent_id=parent_id,
              position=position,
              db_session=db_session,
              *args,
              **kwargs
          )
docs: Shifts ordering to "open a gap" for node insertion,
          begins the shift from given position
  
          :param parent_id:
          :param position:
          :param db_session:
          :return: