largest time for given digits

 1from itertools import permutations
 2
 3class Solution:
 4    def largestTimeFromDigits(self, arr: List[int]) -> str:
 5        def is_valid(h, m):
 6            return 0 <= h <= 23 and 0 <= m <= 59
 7        last_valid = ""
 8        for p in permutations(sorted(arr)):
 9            p1, p2, p3, p4 = p
10            h, m = p1*10 + p2, p3 * 10 + p4
11            if is_valid(h, m):
12                last_valid = f"{p1}{p2}:{p3}{p4}"
13        return last_valid