anchor.diff:  
     gdata = buildPythonPackage rec {
       name = "gdata-${version}";
  -    version = "2.0.17";
  +    version = "2.0.18";
   
       src = pkgs.fetchurl {
         url = "https://gdata-python-client.googlecode.com/files/${name}.tar.gz";
         # sha1 = "d2d9f60699611f95dd8c328691a2555e76191c0c";
  -      sha256 = "0bdaqmicpbj9v3p0swvyrqs7m35bzwdw1gy56d3k09np692jfwmd";
  +      sha256 = "1dpxl5hwyyqd71avpm5vkvw8fhlvf9liizmhrq9jphhrx0nx5rsn";
       };
   
       # Fails with "error: invalid command 'test'"
  
positive.code:   };
  
    goobook = buildPythonPackage rec {
      name = "goobook-1.6";
      disabled = isPy3k;
  
      src = pkgs.fetchurl {
        url    = "https://pypi.python.org/packages/source/g/goobook/${name}.tar.gz";
        sha256 = "05vpriy391l5i05ckl5ja5bswqyvl3rwrbmks9pi46w1813j7p5z";
      };
  
      buildInputs = with self; [ ];
  
negative.code:   };
  
    httplib2 = buildPythonPackage rec {
      name = "httplib2-0.9.1";
  
      src = pkgs.fetchurl {
        url = "https://pypi.python.org/packages/source/h/httplib2/${name}.tar.gz";
        sha256 = "1xc3clbrf77r0600kja71j7hk1218sjiq0gfmb8vjdajka8kjqxw";
      };
  
      meta = {
  