Latest Time You Can Obtain After Replacing Characters — Python

# Time:  O(1)
# Space: O(1)

# greedy
class Solution(object):
    def findLatestTime(self, s):
        """
        :type s: str
        :rtype: str
        """
        result = list(s)
        if result[0] == '?': 
            result[0] = '1' if result[1] == '?' or result[1] <= '1' else '0'
        if result[1] == '?': 
            result[1] = '1' if result[0] == '1' else '9'
        if result[3] == '?':
            result[3] = '5'
        if result[4] == '?':
            result[4] = '9'
        return "".join(result)