_: {
  keys = rec {
    mk = mode: key: action: desc: {
      inherit mode key action;
      options = {
        inherit desc;
        silent = true;
      };
    };

    mk' = mode: key: action:
      mk mode key action null;

    mkWithOpts = mode: key: action: desc: opts:
      (mk mode key action desc)
      // {
        options = opts;
      };

    mkWithOpts' = mode: key: action: opts:
      mkWithOpts mode key action null opts;
  };
}