anchor.diff:  
   buildPythonPackage rec {
     pname = "mat2";
  -  version = "0.12.4";
  +  version = "0.13.0";
   
     disabled = pythonOlder "3.5";
   
  
positive.code:     owner = "jvoisin";
      repo = "mat2";
      rev = version;
      hash = "sha256-HjPr4pb0x2Sdq8ALaZeQRnGHmNAoEV8XUGbhOjY00jc=";
    };
  
    patches = [
  
negative.code:   '';
  
    nativeBuildInputs = [
      gobject-introspection
      wrapGAppsHook
    ];
  
    buildInputs = [
      gdk-pixbuf
      librsvg
      poppler_gi
    ];
  