The None Object — Python 3.11.11 documentation
Description: Note that the PyTypeObject for None is not directly exposed in the Python/C API. Since None is a singleton, testing for object identity (using== in C) is sufficient. There is no PyNone_Check() func...

# The `None` Object

Note that the `PyTypeObject` for `None` is not directly exposed in the Python/C API. Since `None` is a singleton, testing for object identity (using `==` in C) is sufficient. There is no `PyNone_Check()` function for the same reason.

PyObject *Py_None

  The Python `None` object, denoting lack of value. This object has no methods. It needs to be treated just like any other object with respect to reference counts.

Py_RETURN_NONE

  Properly handle returning `Py_None` from within a C function (that is, increment the reference count of `None` and return it.)