cartesian.py

def cartesian(*lists):
    if not lists:
        yield ()
        return
    for item in lists[0]:
        for tup in cartesian(*lists[1:]):
            yield (item,) + tup

# >>> list(cartesian('abc', [1, 2]))
# [('a', 1), ('a', 2), ('b', 1), ('b', 2), ('c', 1), ('c', 2)]