学python之leetcode1863题 python3转python2

只能说python3到python差异还挺大的，3to2工具只能修改一部分：下面是转换前后代码比较，每个地方都很值得推敲
python3代码：

class Solution(object):
    sumnum = [0]
    def dfs(nums: List[int], n: int, xor:int) -> List:
        if n == len(nums):
            Solution.sumnum[0] += xor
            return 0
        Solution.dfs(nums, n + 1, xor^nums[n])
        Solution.dfs(nums, n + 1, xor)

    def subsetXORSum(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        Solution.sumnum[0] = 0
        Solution.dfs(nums, 0, 0)

        return Solution.sumnum[0]

python2

class Solution(object):
    sumnum = [0]
    def dfs(self, nums, n, xor):
        if n == len(nums):
            Solution.sumnum[0] += xor
            return 0
        Solution().dfs(nums, n + 1, xor^nums[n])
        Solution().dfs(nums, n + 1, xor)

    def subsetXORSum(self, nums):
        u"""
        :type nums: List[int]
        :rtype: int
        """
        Solution.sumnum[0] = 0
        Solution().dfs(nums, 0, 0)

        return Solution.sumnum[0]