Python: How to check if a nested list is essentially empty?

Question

Is there a Pythonic way to check if a list (a nested list with elements & lists) is essentially empty? What I mean by

Answer 1

I don't think there is an obvious way to do it in Python. My best guess would be to use a recursive function like this one :

def empty(li):
    if li == []:
        return True
    else:
        return all((isinstance(sli, list) and empty(sli)) for sli in li)

Note that all only comes with Python >= 2.5, and that it will not handle infinitely recursive lists (for example, a = []; a.append(a)).