let
  pkgs = import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/b62d2a95c72fb068aecd374a7262b37ed92df82b.tar.gz") {};
in pkgs.mkShell {
  packages = [
    (pkgs.python313.withPackages (python-pkgs: with python-pkgs; [
      # select Python packages here
      flask
      flask-sqlalchemy
      psycopg2
    ]))
  ];
}