Return statements inside flattened If nodes

[Tirasz]

While testing, i found an oversight regarding the logic of "flattening".

I came across something like this:

def foo(obj):
    if isinstance(obj, someClass) and something()
        if something_else():
            return obj.copy()
        return obj

That got turned into:

def foo(obj):
    match obj:
        case SomeClass() if something() and something_else():
            return obj.copy()
            return obj

This is of course wrong. But Im pretty sure its quite easily fixable, with a simple check.
I need to check if there are any return, continue, break, yield keywords inside of the nested if-node.
The whole idea of flattening is based on the fact, that the code before the nested node (Pre-nest), and the code after it (Post-nest) are always getting executed, if the main condition is true. However, if the nested node contains any of the before mentioned keywords, then this is no longer true.
To be safe, I'm only going to allow flattening, if neither the pre and post-nested code segments, neither the nested if-node itself contains any of the return, continue, break, yield keywords.