2566. Maximum Difference by Remapping a Digit

class Solution:
    def minMaxDifference(self, num: int) -> int:
        snum = str(num)
        maxNum = minNum = snum

        for e in str(num):
            if int(e) < 9 and maxNum == snum:
                maxNum = snum.replace(e, "9")

            if int(e) > 0 and minNum == snum:
                minNum = snum.replace(e, "0")

        return int(maxNum) - int(minNum)