anchor.diff:    # hangs on darwin + sandbox
     doCheck = !stdenv.isDarwin;
   
  +  preCheck = ''
  +    rm test/{test_exempi,test_files}.py
  +  '';
  +
     meta = with lib; {
       homepage = "https://github.com/python-xmp-toolkit/python-xmp-toolkit";
       description = "Python XMP Toolkit for working with metadata";
  
positive.code: 
    buildInputs = [ exempi ];
  
    checkInputs = lib.optionals (pythonOlder "3.3") [ mock ];
  
    propagatedBuildInputs = [ pytz ];
  
    postPatch = ''
  
negative.code: , exempi
  , fetchFromGitHub
  , mock
  , pytz
  , lib, stdenv
  }:
  