code: def setRemoveAction(self, action):
          
          if action not in ('unset', 'delete'):
              raise orb.errors.ValidationError('The remove action must be either "unset" or "delete"')
          else:
              self.__removeAction = action
docs: Sets the remove action that should be taken when a model is removed from the collection generated by
          this reverse lookup.  Valid actions are "unset" or "delete", any other values will raise an exception.
  
          :param action: <str>