Python's wave module works with a specific type of WAV: PCM (WAVE_FORMAT_PCM: 0x0001).
In your case, you're using a WAV of type WAVE_FORMAT_GSM610 [0x0031 = hex(49)].
You can use a program like Audacity or some lib for converting codecs to change the type of the WAV file.
You can see a list of WAV types here: https://www.videolan.org/developers/vlc/doc/doxygen/html/vlc__codecs_8h.html
Python's wave module source code: https://github.com/python/cpython/blob/master/Lib/wave.py
Source : https://stackoverflow.com/questions/17297048/opening-a-wave-file-in-python-unknown-format-49-whats-going-wrong
If you need help with converting the formats or editing the WAV files, I can help.
I did do a search but i did not find that. But thank you in any case.
Are you familiar with the program processing ?