new_contents: class Solution:
      def hammingDistance(self, x: int, y: int) -> int:
          ret = 0
          diff = x ^ y
          while diff > 0:
              bit = diff & 1
              if bit > 0:
                  ret = ret + 1
              diff = diff >> 1
          return ret
  
  
  sol = Solution()
  print(sol.hammingDistance(1, 4))
  
subject: add hamming distance solution(python version)