code: def analog_callback(self, data):
          
          reply = json.dumps({"method": "analog_message_reply", "params": [data[0], data[1]]})
          asyncio.ensure_future(self.websocket.send(reply))
docs: This method handles the analog message received from pymata_core
          :param data: analog callback message
          :returns:{"method": "analog_message_reply", "params": [PIN, DATA_VALUE}