anchor.diff:    src = fetchFromGitHub {
       owner = "prusa3d";
       repo = "Slic3r";
  -    sha256 = "1nrryd2bxmk4y59bq5fp7n2alyvc5a9xvnbx5j4fg4mqr91ccs5c";
  +    sha256 = "0frkjgzmiy788ijkcqz3baxcrncqmk9s2vcd99hb8p2q13cg51ff";
       rev = "version_${version}";
     };
   
  
positive.code:     XMLSAX
    ]);
  
    postInstall = ''
      echo 'postInstall'
      wrapProgram "$out/bin/slic3r-prusa3d" \
  
negative.code: in
  stdenv.mkDerivation rec {
    name = "slic3r-prusa-edition-${version}";
    version = "1.39.1";
  
    enableParallelBuilding = true;
  
  