anchor.diff:    twisted = buildPythonPackage rec {
       # NOTE: When updating please check if new versions still cause issues
       # to packages like carbon (http://stackoverflow.com/questions/19894708/cant-start-carbon-12-04-python-error-importerror-cannot-import-name-daem)
  -
  +    disabled = isPy3k;
  + 
       name = "Twisted-11.1.0";
       src = fetchurl {
         url = "https://pypi.python.org/packages/source/T/Twisted/${name}.tar.bz2";
  
positive.code:   rope = buildPythonPackage rec {
      version = "0.9.4";
      name = "rope-${version}";
  
      src = fetchurl {
        url = "http://pypi.python.org/packages/source/r/rope/${name}.tar.gz";
  
negative.code: 
  
    anyjson = buildPythonPackage rec {
      name = "anyjson-0.3.3";
      disabled = isPy3k;
  
      src = fetchurl {
        url = "http://pypi.python.org/packages/source/a/anyjson/${name}.tar.gz";
        md5 = "2ea28d6ec311aeeebaf993cb3008b27c";
      };
  
      buildInputs = [ pythonPackages.nose ];
  