code: def tx(self, message):
          
          message = message if isinstance(message, list) else [message]
  
          length = len(message)
          length_high_byte = (length & 0xff00) >> 8
          length_low_byte = length & 0x00ff
  
          message_with_length = [length_low_byte, length_high_byte] + message
  
          sum1, sum2 = self._fletcher16_checksum(message_with_length)
          message_with_length.append(sum1)
          message_with_length.append(sum2)
  
          message = [self._START_OF_FRAME]
  
          for b in message_with_length:
              if b in [self._START_OF_FRAME, self._END_OF_FRAME, self._ESC]:
                  message.append(self._ESC)
                  message.append(b ^ self._ESC_XOR)
              else:
                  message.append(b)
  
          message.append(self._END_OF_FRAME)
  
          self._port.write(message)
docs: Transmit a series of bytes
          :param message: a list of bytes to send
          :return: None