anchor.diff:  
       buildInputs = [ pkgs.libxml2 pkgs.libxslt ];
   
  -    meta = { 
  +    meta = {
         description = "Pythonic binding for the libxml2 and libxslt libraries";
         homepage = http://codespeak.net/lxml/index.html;
         license = "BSD";
  
positive.code: 
    trac = buildPythonPackage {
      name = "trac-0.11.5";
      
      src = fetchurl {
        url = http://ftp.edgewall.com/pub/trac/Trac-0.11.5.tar.gz;
        sha256 = "cc3362ecc533abc1755dd78e2d096d1413bc975abc3185318f4821458cd6a8ac";
      };
      
      doCheck = false;
      
      PYTHON_EGG_CACHE = "`pwd`/.egg-cache";
      
      propagatedBuildInputs = [ genshi pkgs.setuptools ];
      
      meta = {
        description = "Enhanced wiki and issue tracking system for software development projects";
        
        license = "BSD";
      };
    };
  
negative.code:     name = "psycopg2-2.0.13";
  
      doCheck = false;
  
      src = fetchurl {
        url = "http://initd.org/pub/software/psycopg/PSYCOPG-2-0/${name}.tar.gz";
        sha256 = "0arkaa1nbbd3pyn4l1bc75wi7nff3vxxh4s8sj5al5hv20p64pm1";
      };
  
      propagatedBuildInputs = [ pkgs.postgresql ];
  
      meta = {
        description = "PostgreSQL database adapter for the Python programming language";
        license = "GPLv2/ZPL";
      };
    };
  
    pycryptopp = buildPythonPackage (rec {
      name = "pycryptopp-0.5.15";
  
  