Generator frames parent

I asked this question elsewhere but it seems to be too advanced for the audience. Basically, can generator frames have parent? What would be the construct?

assert inspect.isgenerator(some_generator)
assert some_generator.gi_frame.f_back is not None  # is this assertion ever possible?
# if yes, what would be the python code for some_generator?

Yes, when the generator is running (e.g. if you ask about yourself).

You mean while the generator is running? Any other cases?

Yes. No. (But threads.)