adding mark.xfail for test with python generator

Author: djarecka

tests/test_generators.py

@@ -8,6 +8,7 @@
 
 
 @pytest.mark.parametrize("model", MODEL_LISTS)
+@pytest.mark.xfail(reason="lack of support for curie in python generator, see issue #2436")
 def test_python_generators(model):
     model_python = PythonGenerator(str(model)).serialize()