How to get the descriptors among the member of a class defined in C++

I am using a module written in C++ and want to get all data descriptors of an object.
Doing the following, the list descriptors is empty.

import inspect
from imported_cpp_module import A

a = A()

descriptors = [
    (desc, obj)
    for desc, obj in inspect.getmembers(a)
    if inspect.isdatadescriptor(obj)

I can see in the implementation of imported_cpp_module that the members that I want, aaa and bbb, are in tp_getset. How to distinguish these from, say __class__, __delattr__, __dir__ etc?

A_PyObj::s_getset[] =
    {"aaa", (getter)aaa_getter, (setter)aaa_setter, "aaa <-> str. Sets or queries the aaa member", nullptr}
    , {"bbb", (getter)bbb_getter, nullptr, "bbb -> int. Returns the bbb member", nullptr}
    , {NULL}

A_PyObj::s_PyTypeDef =
    .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
    .tp_name = "A"
    , .tp_basicsize = sizeof(A)
    , .tp_dealloc = (destructor)dealloc
    , .tp_flags = Py_TPFLAGS_DEFAULT
    , .tp_doc = "An A object with members aaa and bbb"
    , .tp_getset = s_getset
    , .tp_base = &Base_PyObj::s_PyTypeDef

I should have asked getmembers(A), the class, not its instance.