This is strange. I tried your snippet with your file and it works for me:
(env) ➜ testing cat x.py
from mutagen.id3 import ID3
tags = ID3("myfile.mp3")
print(tags["TXXX:FMPS_Rating_Amarok_Score"])
(env) ➜ testing python x.py
0.78
I deeply resonate with the sentiments in this article. It brilliantly articulates the topic in a way that I didn't have the language for.
It's more important than ever in today's homogenized internet monoculture to advocate for such things, especially for those outside the tech sphere. Great read!