anchor.diff:  
   
     mutagen = buildPythonPackage (rec {
  -    name = "mutagen-1.20";
  -
  -    src = fetchurl {
  -      url = "http://mutagen.googlecode.com/files/${name}.tar.gz";
  -      sha256 = "1rz63nh7r6qj3zsidf8d3a7ih647prvvqzi51p8dqkqmvrwc8mky";
  -    };
  +    name = "mutagen-1.23";
  +
  +    src = fetchurl {
  +      url = "http://pypi.python.org/packages/source/m/mutagen/${name}.tar.gz";
  +      sha256 = "12f70aaf5ggdzll76bhhkn64b27xy9s1acx417dbsaqnnbis8s76";
  +    };
  +    
  +    # one unicode test fails
  +    doCheck = false;
   
       meta = {
         description = "Python multimedia tagging library";
  
positive.code:   };
  
    beets = buildPythonPackage rec {
      name = "beets-1.0.0";
  
      src = fetchurl {
        url = "http://pypi.python.org/packages/source/b/beets/${name}.tar.gz";
        md5 = "88ad09a93aa0d69ce813205cf23b2a6c";
      };
  
      # tests depend on $HOME setting
  
negative.code: 
  
    six = buildPythonPackage rec {
      name = "six-1.7.3";
  
      src = fetchurl {
        url = "http://pypi.python.org/packages/source/s/six/${name}.tar.gz";
        md5 = "784c6e5541c3c4952de9c0a966a0a80b";
      };
  
      # error: invalid command 'test'
  