This method handles the analog message received from pymata_core
        :param data: analog callback message
        :returns:{"method": "analog_message_reply", "params": [PIN, DATA_VALUE}

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