anchor.diff:  
   
     flake8 = buildPythonPackage (rec {
  -    name = "flake8-1.7.0";
  +    name = "flake8-2.0";
   
       src = fetchurl {
         url = "http://pypi.python.org/packages/source/f/flake8/${name}.tar.gz";
  -      md5 = "a7830d1a6c23e889bc1fcaa4a87f53bd";
  +      md5 = "176c6b3613777122721db181560aa1e3";
       };
   
       buildInputs = [ nose ];
  +    propagatedBuildInputs = [ pyflakes pep8 mccabe ];
   
       # 3 failing tests
  -    doCheck = false;
  +    #doCheck = false;
   
       meta = {
         description = "code checking using pep8 and pyflakes.";
  
positive.code:     meta = {
        homepage = "http://home.blarg.net/~steveha/pyfeed.html";
        description = "Tools for syndication feeds";
      };
    };
  
  
negative.code: 
    pep8 = buildPythonPackage rec {
      name = "pep8-${version}";
      version = "1.4.5";
  
      src = fetchurl {
        url = "http://pypi.python.org/packages/source/p/pep8/${name}.tar.gz";
        md5 = "055dbd22ac5669232fdba752612e9686";
      };
  
      #======================================================================
      #FAIL: test_check_simple (testsuite.test_shell.ShellTestCase)
      #----------------------------------------------------------------------
      #Traceback (most recent call last):
      #  File "/tmp/nix-build-python-pep8-1.4.5.drv-0/pep8-1.4.5/testsuite/test_shell.py", line 84, in test_check_simple
      #    self.assertTrue(config_filename.endswith('tox.ini'))
      #AssertionError: False is not true
      #
      #----------------------------------------------------------------------
      #Ran 21 tests in 0.711s
      #
      #FAILED (failures=1)
      doCheck = false;
  
      meta = {
        homepage = "http://pep8.readthedocs.org/";
        description = "Python style guide checker";
        license = pkgs.lib.licenses.mit;
        maintainers = [ stdenv.lib.maintainers.garbas ];
      };
    };
  
  