leetcode解决单个数字问题，无需额外的内存

I've come across a solution to the single number problem from https://www.youtube.com/watch?v=-_6l_ijmcgs which proposes solution below

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        result = 0 
        for i,num in enumerate(nums):
            result ^= num 
        return result 

但是由于空间复杂度始终为O（1），因此这在技术上不是使用额外的内存吗？