Create a superset efficiently in Python

superset.py

#!/usr/bin/env python
"""
Create a superset from the integers provided

e.g. ./superset.py 1 2 3

[set([]), set([1]), set([2]), set([3]), set([1, 2]),
 set([1, 3]), set([2, 3]), set([1, 2, 3])]
"""
import sys


def main(*numbers):
    sets = [set([])]
    for n in numbers:
        sets.extend([s | {n} for s in sets])
    print sets


if __name__ == '__main__':
    numbers = [int(i) for i in sys.argv[1:]]
    main(*numbers)