Python global vs dict

Question

Why does the following variable not pass to the closure:

def something():
    UPDATED = 0
    def _inner():
        UPDATED += 1

But this one does:

def something():
    UPDATED = {0:0}
    def _inner():
        UPDATED[0] += 1

I find myself using the latter approach as a sort of hack to get around referencing a global var, but why does that one work and the first doesn't?