code: def from_raw_message(cls, rawmessage):
          
          if (rawmessage[5] &
                  MESSAGE_FLAG_EXTENDED_0X10) == MESSAGE_FLAG_EXTENDED_0X10:
              if len(rawmessage) >= ExtendedSend.receivedSize:
                  msg = ExtendedSend.from_raw_message(rawmessage)
              else:
                  msg = None
          else:
              msg = StandardSend(rawmessage[2:5],
                                 {'cmd1': rawmessage[6],
                                  'cmd2': rawmessage[7]},
                                 flags=rawmessage[5],
                                 acknak=rawmessage[8:9])
          return msg
docs: Create a message from a raw byte stream.