> Does it makes sense to have the presence of "global a" in g, block all possibility for h, to access it's grand parent's a ?

From the perspective of ML-style languages with pure lexical scoping, no, it does not make sense.


But Python started with C-like simple name spaces, then nested functions and 'nonlocal' were added.


I think the answer (as usual) is that people may rely on the established convention and that it is no problem in practice.