如何遍历列表并比较两个数字之间的和，最终返回具有最接近索引分组的答案？

def find_closest_group(nums):
    target_sum = sum(nums) // 2  # 目标和为列表元素和的一半
    closest_sum = float('inf')  # 初始化最接近索引分组的和为正无穷大
    closest_index = -1  # 初始化最接近索引分组的索引为-1

    for i in range(len(nums)):
        for j in range(i+1, len(nums)):
            current_sum = nums[i] + nums[j]  # 计算两个数字之间的和
            diff = abs(current_sum - target_sum)  # 计算当前和与目标和之间的差值

            if diff < abs(closest_sum - target_sum):
                closest_sum = current_sum  # 更新最接近索引分组的和
                closest_index = i  # 更新最接近索引分组的索引

    return nums[closest_index] if closest_index != -1 else None

# 示例用法
nums = [1, 2, 3, 4, 5]
result = find_closest_group(nums)
print(result)  # 输出最接近索引分组的答案