{
  perSystem = {
    inputs',
    config,
    pkgs,
    ...
  }: let
    # use nixpkgs lib instead of flake-parts lib
    # avoids home-manager warning about version mismatch
    inherit (pkgs) lib;
  in {
    _module.args.lib = lib.extend (
      final: prev: {
        my = let
          lib = final;
          getPaths = file: root:
            builtins.filter builtins.pathExists (
              map (dir: root + "/${dir}/${file}") (
                lib.attrNames (lib.filterAttrs (name: type: type == "directory") (builtins.readDir root))
              )
            );
        in {
          inherit getPaths;
          getModules = builtins.concatMap (getPaths "default.nix");
          getHmModules = builtins.concatMap (getPaths "home.nix");
        };
      }
    );
  };
}