final: prev: {
  # xonsh = prev.xonsh.overridePythonAttrs (old: rec {
  #   version = "0.12.4";
  #   src = final.fetchFromGitHub {
  #     owner = "xonsh";
  #     repo = "xonsh";
  #     rev = version;
  #     sha256 = "0kdps0gf0767zy0fs6qn39rv4z3x7ck0qz1pzx6962593171yk8b";
  #   };
  #   propagatedBuildInputs = prev.xonsh.propagatedBuildInputs ++ [final.python3Packages.virtualenv];
  #   disabledTests = prev.xonsh.disabledTests ++ ["test_commands_cache" "test_ptk_highlight" "test_command_completers"];
  # });

  # python39 = prev.python39.override {
  #   self = prev.python39;
  #   packageOverrides = python_final: python_super: {
  #     prompt-toolkit = python_super.prompt-toolkit.overridePythonAttrs (old: rec {
  #       version = "3.0.29";
  #       src = python_final.fetchPypi {
  #         pname = "prompt_toolkit";
  #         inherit version;
  #         sha256 = "sha256-vWQPYOjOzXTw3CSXE9QzrOLdxitl7gf5bTWOCxUrbqc=";
  #       };
  #     });
  #   };
  # };

  # Using mach-nix to fetch unpackaged xontrib plugins
  # adapted from https://github.com/NixOS/nixpkgs/issues/75786#issuecomment-873654103
  mach-nix = import (builtins.fetchGit {
    url = "https://github.com/DavHau/mach-nix/";
    ref = "refs/tags/3.5.0";
  }) {
    pkgs = final;
  };

  xonsh_pyenv = final.mach-nix.mkPython {
    requirements = ''
    xontrib-fzf-widgets
    xonsh-direnv
    '';
  };

  xonsh_with_plugins = final.xonsh.overridePythonAttrs (old: {
    propagatedBuildInputs = old.propagatedBuildInputs ++ final.xonsh_pyenv.python.pkgs.selectPkgs final.xonsh_pyenv.python.pkgs;
  });
}