给定一个整数数组 nums，下面代码找到一个具有最大和的连续子数组，并返回其最大和。则下面说法错误的是（ ）。

import math
def crossSum(nums, left, mid, right):
    leftSum = -math.inf
    sum_val = 0
    for i in range(mid, left - 1, -1):
        sum_val += nums[i]
        leftSum = max(leftSum, sum_val)

    rightSum = -math.inf
    sum_val = 0
    for i in range(mid + 1, right + 1):
        sum_val += nums[i]
        rightSum = max(rightSum, sum_val)

    return leftSum + rightSum

def helper(nums, left, right):
    if left == right:
        return nums[left]

    mid = left + (right - left) // 2
    leftMax = helper(nums, left, mid)
    rightMax = helper(nums, mid + 1, right)
    crossMax = crossSum(nums, left, mid, right)

    return max(leftMax, rightMax, crossMax)

def maxSubArray(nums):
    return helper(nums, 0, len(nums) - 1)