[Python]"17"과 같은 문자열로 순열구하기

from itertools import permutations

def solution(numbers):
    a = set()
    for i in range(len(numbers)):
        a |= set(map(int, map("".join, permutations(list(numbers), i + 1))))
    

a의 값
{1, 71, 17, 7}