How to add a python module/package to a nix/python overlay?

I also just figured out that when I add the “withPackages” to the src line of the overlay, it breaks the part in the installPhase where it sets the LD_LIBRARY_PATH.

You can test it by adding the “withPackages” suggested above and running whispernow in terminal, which should throw this libz.so.1 error. Then comment the withPackages out, and the error goes away.