Multiple Python versions with poetry2nix

shell.nix

{ pkgs ? import <nixpkgs> {} }:

let
  makeEnv = python: pkgs.poetry2nix.mkPoetryEnv {
    python = python;
    pyproject = ./pyproject.toml;
    poetrylock = ./poetry.lock;
    overrides = [
      pkgs.poetry2nix.defaultPoetryOverrides
      (self: super: {
        # overridding python-box
        python-box = super.python-box.overridePythonAttrs(old: {
          buildInputs = old.buildInputs ++ [
            self.pytestrunner
          ];
        });
      })
    ];
  };
in
{
  py38 = makeEnv pkgs.python38;
}

To run:

nix-shell -A py38