anchor.diff:  
     stompclient = buildPythonPackage (rec {
       name = "stompclient-0.3.2";
  +    disabled = isPy3k;
   
       src = fetchurl {
         url = "http://pypi.python.org/packages/source/s/stompclient/${name}.tar.gz";
  
positive.code:   });
  
    sigal = buildPythonPackage rec {
      name = "sigal-0.5.0";
  
      src = fetchurl {
        url = "http://pypi.python.org/packages/source/s/sigal/${name}.tar.gz";
        md5 = "93c93725674c0702583a638f5a09c9e4";
      };
  
      propagatedBuildInputs = [ jinja2 markdown pillow pilkit clint argh pytest ];
  
negative.code: 
    async = buildPythonPackage rec {
      name = "async-0.6.1";
      disabled = isPy3k;
      meta.maintainers = [ stdenv.lib.maintainers.mornfall ];
  
      buildInputs = [ pkgs.zlib ];
  