ok - because when running pip install -U audiocraft command from op inside nix-shell -p ffmpeg ffmpeg.dev pkg-config python313Packages.spacy python313Packages.av I still seem to get the error in op — either a python3.9-specific av or libsw library needs to be installed via Nix or the solution to op is unrelated.
From your response I’m unsure if you’re suggesting I somehow revert to an earlier nixos channel or installing python3.9 at all so I’ll note that I have installed python3.9 already via
cachix use nixpkgs-python
nix shell github:cachix/nixpkgs-python#'"3.9"'
as suggested here