anchor.diff:  
   
     anyjson = buildPythonPackage rec {
  -    name = "anyjson-0.3.1";
  +    name = "anyjson-0.3.3";
  +    disabled = isPy3k;
   
       src = fetchurl {
         url = "http://pypi.python.org/packages/source/a/anyjson/${name}.tar.gz";
  -      md5 = "2b53b5d53fc40af4da7268d3c3e35a50";
  +      md5 = "2ea28d6ec311aeeebaf993cb3008b27c";
       };
   
       buildInputs = [ pythonPackages.nose ];
  
positive.code: 
    urlgrabber =  buildPythonPackage rec {
      name = "urlgrabber-3.9.1";
  
      src = fetchurl {
        url = "http://urlgrabber.baseurl.org/download/${name}.tar.gz";
  
negative.code:   rope = buildPythonPackage rec {
      version = "0.9.4";
      name = "rope-${version}";
      
      disabled = isPy3k;
  
      src = fetchurl {
        url = "http://pypi.python.org/packages/source/r/rope/${name}.tar.gz";
  