Roman to integer : leetcode solution in python

class Solution:
    def romanToInt(self, s: str) -> int:
        try:
            roman = {"I":1,"V":5,"X":10,"L":50,"C":100,"D":500,"M":1000}
            res = 0
            for i in range(len(s)):
                if i + 1 < len(s) and roman[s[i]] < roman[s[i+1]]:
                    res -= roman[s[i]]
                else:
                    res += roman[s[i]]
            return res
        except Exception as e:
            print(e)