That one is a library but it contains also a unityextract python script that uses such library for extraction:
python unityextract.py --all YOUR_FILE.assets
For other questions try here first:https://github.com/HearthSim/UnityPack/issues
Probably was better to post here because it's a whole topic about Unity:https://zenhax.com/viewtopic.php?f=17&t=12
How I can to use python script? I downloaded Python 3.6 and python-lz4. I need to download something? Where I can execute command python unityextract.py --all YOUR_FILE.assets
Sorry, I'm very newbie with python.