code: def response_delay(self, delay):
          
          if isinstance(delay, (int, float)) and delay >= 0 or delay is None:
              self._response_delay = delay
          else:
              raise ValueError(
                  _format("Invalid value for response_delay: {0!A}, must be a "
                          "positive number", delay))
docs: Setter method; for a description see the getter method.