anchor.diff:    nipy = buildPythonPackage rec {
       version = "0.4.0";
       name = "nipy-${version}";
  - 
  +
       disabled = pythonOlder "2.6";
   
       checkPhase = ''    # wants to be run in a different directory
  
positive.code:     ];
  
      meta = {
        homepage = https://github.com/inducer/pytools/; 
        description = "Miscellaneous Python lifesavers.";
        license = licenses.mit;
        maintainers = with maintainers; [ artuuge ];
  
negative.code:     };
    };
  
    pytools = buildPythonPackage rec {
      name = "pytools-${version}";
      version = "2016.2.1";
  
      src = pkgs.fetchFromGitHub {
        owner = "inducer";
  