As you can read here: https://github.com/Marco-Sulla/python-frozendict/issues/37
Py_IS_TYPE(op, &PyDict_Type) did not work on MacOS. I had to use PyDict_Check. Why don't I have this problem with Linux? PS: since I'm creating a modified version of dict, I copied the dict internal source and I link against them. Maybe the problem is correlated. -- https://mail.python.org/mailman/listinfo/python-list
