python 简单遍历

有两种情况，要么存在要么不存在

class Solution:
    def MoreThanHalfNum_Solution(self, numbers):
        # write code here
        if len(numbers) == 1:
            return numbers[0]
        num = None
        for i in numbers:
            if i == num:
                return i
            num = i 
        return 0