code: def play_tone(self, pin, tone_command, frequency, duration=None):
          
          task = asyncio.ensure_future(self.core.play_tone(pin, tone_command,
                                                           frequency, duration))
          self.loop.run_until_complete(task)
docs: This method will call the Tone library for the selected pin.
          It requires FirmataPlus to be loaded onto the arduino
  
          If the tone command is set to TONE_TONE, then the specified
          tone will be played.
  
          Else, if the tone command is TONE_NO_TONE, then any currently
          playing tone will be disabled.
  
  
          :param pin: Pin number
  
          :param tone_command: Either TONE_TONE, or TONE_NO_TONE
  
          :param frequency: Frequency of tone
  
          :param duration: Duration of tone in milliseconds
  
          :returns: No return value