关于leetcode 里py的书写的格式

def twoSum(self, nums:List[int], target:int)->List[int]: 为什么这行要这么写，我照写在idea里报错了
def twoSum(self, nums, target): 改成这样才不报错

望采纳支持，谢谢！

def twoSum(nums, target):
    n = len(nums)
    for i in range(n):
        for j in range(i + 1, n):
            if nums[i] + nums[j] == target:
                return [i, j]
    return []


if __name__ == '__main__':
    nums = [2, 7, 11, 15]
    target = 9
    print(twoSum(nums, target))

顺便帮忙改下代码，报错打印输出不了，不知道该怎么打印输出这个

print(twoSum(nums = [2,7,11,15], target = 9))
def twoSum(self, nums, target):
    n = len(nums)
    for i in range(n):
         for j in range(i + 1, n):
              if nums[i] + nums[j] == target:
                return [i, j]

    return []