lib: _: rec {
  my = import ./my.nix lib;

  dns = import ./dns.nix;

  isEven = number:
    assert (builtins.isInt number) || (builtins.isFloat number);
      builtins.div number 2 == 0;

  isOdd = !isEven;

  pow = base: exponent:
    assert (builtins.isInt base) && (builtins.isInt exponent);
    assert exponent > 0;
      builtins.foldl' (x: _: x * base) 1 (builtins.genList (_: _) exponent);

  mapListToAttrs = f: attrs:
    builtins.listToAttrs (map (name: {
        name =
          if builtins.isList name
          then builtins.elemAt name (builtins.length name - 1)
          else name;
        value = f name;
      })
      attrs);

  mkTcpMem = min: ini: max:
    assert min <= ini && ini <= max;
      lib.concatMapStrings (x: toString x + " ") (map (pow 2) [min ini max]);

  moduleFromRef = module: ref: sha256: {
    disabledModules = [module];
    imports = [
      (let
        src = builtins.fetchTarball {
          url = let
            cons = lib.splitString ":" ref;
            owner = lib.head cons;
            branch = lib.last cons;
          in "https://github.com/${owner}/nixpkgs/archive/refs/heads/${branch}.tar.gz";
          inherit sha256;
        };
      in "${src}/nixos/modules/${module}")
    ];
  };
}