python: make a string list contain all combination of lowercase charchters

make_str_list.py

from itertools import product
from string import lowercase

def test(n):
    result = []
    for i in range(n):
        result.extend(''.join(v) for v in product(lowercase, repeat=i+1))
    return result

print test(2)
['a', 'b', 'c', ... 'zy', 'zz']