anchor.diff:      mkdir -p $out/bin
       cp $src/carddav-util.py $out/bin
   
  -    pythondir="$out/lib/${python.libPrefix}/site-packages"
  +    pythondir="$out/lib/${python3Packages.python.sitePackages}"
       mkdir -p "$pythondir"
       cp $src/carddav.py "$pythondir"
     '';
  
positive.code: 
    nativeBuildInputs = [ makeWrapper ];
  
    propagatedBuildInputs = with pythonPackages; [ requests vobject lxml ];
  
    doCheck = false; # no test
  
  
negative.code: { lib, stdenv, fetchgit, python3Packages, makeWrapper }:
  
  stdenv.mkDerivation {
  
  