anchor.diff:  
       export HOME=$(mktemp -d)
   
  -    mkdir -p $out/share/themes
       bash install.sh -d $out/share/themes -t all \
         ${lib.optionalString (size != "") "-s ${size}"} \
         ${lib.optionalString (tweaks != []) "--tweaks " + builtins.toString tweaks}
  
positive.code: 
  stdenvNoCC.mkDerivation rec {
    pname = "catppuccin-gtk";
    version = "unstable-2022-08-01";
  
    src = fetchFromGitHub {
      repo = "gtk";
      owner = "catppuccin";
      rev = "87a79fd2bf07accc694455df30a32a82b1b31f4f";
      sha256 = "sha256-dKHTQva0BYkO6VPNfY/pzRn/V1ghX+tYqbnM9hTAMeE=";
    };
  
    nativeBuildInputs = [ gtk3 sassc which ];
  
    buildInputs = [ gnome-themes-extra ];
  
  
negative.code:   validTweaks = [ "nord" "dracula" "black" "rimless" "normal" ];
  
    unknownTweaks = lib.subtractLists validTweaks tweaks;
    illegalMix = (lib.elem "nord" tweaks) && (lib.elem "dracula" tweaks);
  
    assertIllegal = lib.assertMsg (!illegalMix) ''
      Tweaks "nord" and "dracula" cannot be mixed. Tweaks: ${toString tweaks}
    '';
  
  