count the number with unique digit

class Solution:
    def countNumbersWithUniqueDigits(self, n: int) -> int:
        if n==0:
            return 1
        unique = 10
        can_expand = 9
        for digits in range(2,min(n,10)+1):
            can_expand *= (11- digits)
            print(can_expand)
            unique += can_expand
        return unique