anchor.diff:      };
     };
   
  -  configparser = buildPythonPackage rec {
  +  # Backported version of the ConfigParser library of Python 3.3
  +  configparser = if isPy3k then null else buildPythonPackage rec {
       name = "configparser-${version}";
       version = "3.3.0r2";
   
  
positive.code:   pybrowserid = buildPythonPackage rec {
      name = "PyBrowserID-${version}";
      version = "0.9.2";
      src = pkgs.fetchgit {
        url = https://github.com/mozilla/PyBrowserID.git;
        rev = "refs/tags/${version}";
  
negative.code:   konfig = buildPythonPackage rec {
      name = "konfig-${version}";
      version = "0.9";
  
      # konfig unconditionaly depend on configparser, even if it is part of
      # the standard library in python 3.2 or above.
      disabled = isPy3k;
  
      src = pkgs.fetchgit {
        url = https://github.com/mozilla-services/konfig.git;
        rev = "refs/tags/${version}";
  