{ pkgs ? import <nixpkgs> { }, python ? pkgs.python39, ... }:
pkgs.mkShell {
  nativeBuildInputs = with pkgs; [ (python.withPackages (ps: with ps; [ pip wheel ])) poetry git ];
  shellHook = ''
    [ -d .venv ] || python -m venv .venv
    source .venv/bin/activate
  '';
}