code: def bytes(self):
          
          flagByte = 0x00
          messageType = 0
          if self._messageType is not None:
              messageType = self._messageType << 5
          extendedBit = 0 if self._extended is None else self._extended << 4
          hopsMax = 0 if self._hopsMax is None else self._hopsMax
          hopsLeft = 0 if self._hopsLeft is None else (self._hopsLeft << 2)
          flagByte = flagByte | messageType | extendedBit | hopsLeft | hopsMax
          return bytes([flagByte])
docs: Return a byte representation of the message flags.