anchor.diff:  assert is2x -> !isPy3;
   
   stdenv.mkDerivation rec {
  -  name = "pygobject-${source.version}${optionalString is2x "-${source.date}"}";
  +  name = "pygobject-${source.version}";
   
  -  src =
  -    if is2x then
  -      fetchFromGitHub {
  -        version = source.fetchzipversion;
  -        owner = "GNOME";
  -        repo = "pygobject";
  -        inherit (source) rev sha256;
  -      }
  -    else
  -      fetchurl {
  -        url = "mirror://gnome/sources/pygobject/${channel}/${name}.tar.xz";
  -        hashOutput = false;
  -        inherit (source) sha256;
  -      };
  -
  -  nativeBuildInputs = optionals is2x [
  -    autoreconfHook
  -  ];
  +  src = fetchurl {
  +    url = "mirror://gnome/sources/pygobject/${channel}/${name}.tar.xz";
  +    hashOutput = false;
  +    inherit (source) sha256;
  +  };
   
     buildInputs = [
  -    cairo
       glib
       gobject-introspection
       libffi
  +    python
  +  ] ++ optionals (!is2x) [
  +    cairo
       pycairo
  -    python
     ];
   
     configureFlags = optionals is2x [
  
positive.code: 
    sources = {
      "2.28" = {
        version = "2.28";
        date = "2013-02-19";
        # Latest commit from pygobject-2-28 branch
        rev = "9456ba70fdb98b3a4eb7ee2f630182387a54ca00";
        sha256 = "bf61ddfa54b9af5ff4ed4321ac2a8f613da334e88f481a53a634dd7d08509327";
        fetchzipversion = 2;
      };
      "3.26" = {
        version = "3.26.1";
  
negative.code: { stdenv
  , fetchurl
  , isPy3
  , lib
  