[QUESTION] what is extract_block supposed to do?

[AckslD]

I'm just trying to understand the different features and tried some things on this python snippet:

def f(a, b):
    if True:
        y = a + b
        z = y + b
    return z + y

If I call Refactor extract_block (either in visual mode or not) and give the new function the name test I get:

def test(a, b):
    if True:
        y = a + b
        z = y + b
    return z + y



def f(a, b):
    test(a, b)

which I'm not sure what's the purpose, seems like just a copy of the function and f is now broken since it doesn't return anything.