Py_IS_TYPE(op, &PyDict_Type) does not work on MacOS

[Marco Sulla]

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.