Convenience to string method.

def device_radio_str(self, resp, indent="  "):
        """Convenience to string method.
        """
        signal = resp.signal
        tx = resp.tx
        rx = resp.rx
        s = "Wifi Signal Strength (mW): {}\n".format(signal)
        s += indent + "Wifi TX (bytes): {}\n".format(tx)
        s += indent + "Wifi RX (bytes): {}\n".format(rx)
        return s