code: def _validate_message(self, message):
          
          if message.task_uuid != self.task_uuid:
              raise WrongTask(self, message)
          if not message.task_level.parent() == self.task_level:
              raise WrongTaskLevel(self, message)
docs: Is C{message} a valid direct child of this action?
  
          @param message: Either a C{WrittenAction} or a C{WrittenMessage}.
  
          @raise WrongTask: If C{message} has a C{task_uuid} that differs from the
              action's C{task_uuid}.
          @raise WrongTaskLevel: If C{message} has a C{task_level} that means
              it's not a direct child.