Include a package's python library in the $PYTHONPATH of the package's application?

I’m trying to add the app Bubblejail to nixpkgs, and I’ve hit a snag. Most of its code exists in a library module that gets placed in lib during install. The actual executables import from that module at runtime. The problem is that the interpreter can’t find the bubblejail module because it isn’t included in the dependencies of the app because that would cause a cyclical dependency. I tried packaging the library separately, but I still can’t seem to include python312Packages.bubblejail as a dependency of bubblejail.

How can I get the runtime inperpreter to find the bubblejail module in this scenario?