new_contents: class Solution:
      # @return an integer
  
      def romanToInt(self, s):
          res = 0
          table = {
              'M': 1000, 'MC': 900, 'D': 500, 'DC': 400, 'C': 100, 'CX': 90,
              'L': 50, 'LX': 40, 'X': 10, 'XI': 9, 'V': 5, 'VI': 4, 'I': 1
          }
          symbols = [
              'M', 'MC', 'D', 'DC', 'C', 'CX', 'L', 'LX', 'X', 'XI',
              'V', 'VI', 'I'
          ]
          s = s[::-1]
          while s:
              for symbol in symbols:
                  if s.endswith(symbol):
                      res += table[symbol]
                      s = s[:-len(symbol)]
                      break
          return res
  
subject: add solution for Roman to Integer