'utf-8' codec can't decode byte 0x9d in position 0: invalid start byte

[Peter-3mad]

I'm trying to use the library as part of a backend project so i got the code files not the command line tool, the encoding goes just fine. but whenever I try to decode I get this error..
this is the line that causes the problem, in the read_message function

text = bytes(msg[start:end]).decode('utf-8')