anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "gnome-calculator";
  -  version = "42.beta";
  +  version = "42.rc";
   
     src = fetchurl {
       url = "mirror://gnome/sources/gnome-calculator/${lib.versions.major version}/${pname}-${version}.tar.xz";
  -    sha256 = "9nruUc/Ql9pdJ7uU/o0JCkpopfd90boL5fN4X6KFKu0=";
  +    sha256 = "1quQqyiDQc/WQYAkmT5FdW8+es8CVSV2IH9q1R5qBlA=";
     };
   
     nativeBuildInputs = [
  
positive.code:   ];
  
    doCheck = true;
  
    postPatch = ''
      chmod +x meson_post_install.py # patchShebangs requires executable file
      patchShebangs meson_post_install.py
    '';
  
    preCheck = ''
      # Currency conversion test tries to store currency data in $HOME/.cache.
  
negative.code:     gettext
      itstool
      wrapGAppsHook
      gobject-introspection # for finding vapi files
    ];
  
  