Example code not working

[ClashSAN]

encoded the image, then decoding returned nothing, not "test" like expected.

edit: tried with a different png image: Traceback (most recent call last): File "/home/me/whisper/decode.py", line 8, in print(watermark.decode('utf-8')) UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte