LeetCode - Roman to Integer

Given a roman numeral, convert it to an integer.

Input is guaranteed to be within the range from 1 to 3999.

Input format is 'String'
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Sample Input: 'XXVII'
Output : 27
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def romanToInt(self, num):

 dic = {'I': 1, 'V': 5, 'X': 10, 'L':50, 'C':100, 'D': 500, 'M': 1000}

 l = len(num)

 integer = dic[num[l-1]]



for i in range(l-1,0,-1):

 if dic[num[i]] <= dic[num[i-1]]:

  integer += dic[num[i-1]]

 else:

  integer -= dic[num[i-1]]

return integer