let 
  names = [ "pennyworth" "jarvis" "blackadder" "woodhouse" "frumar" "zazu" ];
in
pkgs: super: {
  yorick = rec {
    nixos =
      configuration: extraArgs:
      let
        c = import (pkgs.path + "/nixos/lib/eval-config.nix") {
          inherit (pkgs.stdenv.hostPlatform) system;
          inherit extraArgs;
          modules =
            [(
              { lib, ... }: {
                config.nixpkgs.pkgs = lib.mkDefault pkgs;
              }
            )] ++ (
              if builtins.isList configuration
              then configuration
              else [configuration]
            );
        };
      in
        c.config.system.build // c;
  };
  yorick.machine = pkgs.lib.genAttrs names (name: nixos [
    ./roles
    (./logical + "/${name}.nix")
  ] {
    inherit name;
  });
}