{ pkgs ? import <nixpkgs> {}, shell ? false }:
let
    pyenv = pypkgs: with pypkgs; [
        greenlet twisted cython mysqlclient bcrypt
    ];
    buildInputs = [ (pkgs.python2.withPackages pyenv) ];
in
if shell then
  pkgs.mkShell { inherit buildInputs; }
else
  pkgs.stdenv.mkDerivation {
      name = "marmots";
      src = ./.;
      inherit buildInputs;
      installPhase = ''
        mkdir $out
        cp -R * $out
      '';
  }