anchor.diff:  
   
     pyramid = buildPythonPackage rec {
  -    name = "pyramid-1.5.1";
  +    name = "pyramid-1.5.2";
   
       src = pkgs.fetchurl {
         url = "http://pypi.python.org/packages/source/p/pyramid/${name}.tar.gz";
  -      md5 = "8a1ab3b773d8e22437828f7df22852c1";
  +      md5 = "d56b140b41d42f818f4349d94d968c9a";
       };
   
       preCheck = ''
  
positive.code:   });
  
    waitress = buildPythonPackage rec {
      name = "waitress-0.8.7";
  
      src = pkgs.fetchurl {
        url = "http://pypi.python.org/packages/source/w/waitress/${name}.tar.gz";
        md5 = "714f3d458d82a47f12fb168460de8366";
      };
  
      doCheck = false;
  
negative.code: 
  
    mccabe = buildPythonPackage (rec {
      name = "mccabe-0.3";
  
      src = pkgs.fetchurl {
        url = "http://pypi.python.org/packages/source/m/mccabe/${name}.tar.gz";
        md5 = "81640948ff226f8c12b3277059489157";
      };
  
      meta = {
        description = "McCabe checker, plugin for flake8";
  