Count Good Numbers LeetCode solution in Python

1
class Solution:
2
    def countGoodNumbers(self, n: int) -> int:
3
        ans = 1
4
        rem = n % 2
5
        n -= rem
6
        ans = pow(20, n // 2, 10**9 + 7)
7
        if rem == 1:
8
            ans *= 5
9
        return ans % (10**9 + 7)