anchor.diff:  
   
     httplib2 = buildPythonPackage rec {
  -    name = "httplib2-0.7.6";
  +    name = "httplib2-0.7.7";
   
       src = fetchurl {
         url = "http://httplib2.googlecode.com/files/${name}.tar.gz";
  -      sha256 = "baa7bf431fa9d3c1016562de717e1ebb322a99df72a2918f6b5b8f65fa65bc2e";
  +      sha256 = "2e2ce18092c32d1ec54f8a447e14e33585e30f240b883bfeeca65f12b3bcfaf6";
       };
   
       doCheck = false; # doesn't have a test
  
positive.code: 
  
    urwid = buildPythonPackage (rec {
      name = "urwid-1.0.2";
  
      doCheck = false;
  
      src = fetchurl {
        url = "http://excess.org/urwid/${name}.tar.gz";
        md5 = "00542bbd15fae7ea60b02a7570edee2b";
      };
  
      meta = {
  
negative.code: 
  
    alot = buildPythonPackage rec {
      rev = "09804636609b4245cde4faceddffdb5361f3d390";
      name = "alot-0.3.3_${rev}";
  
      src = fetchurl {
        url = "https://github.com/pazz/alot/tarball/${rev}";
        name = "${name}.tar.bz";
        sha256 = "b5239c4dfcd9882608fb48ef80fe9ba9223949ab7e6a2c1abe970ac307ebcd4a";
      };
  
      doCheck = false;
  