给定一个二叉树，返回每一层中最大的节点值，结果以数组形式返回，横线处应填入（    ）。

from collections import deque
import math
from typing import List, Optional

class TreeNode:
	def __init__(self, val=0, left=None, right=None):
		self.val = val
		self.left = left
		self.right = right

def largestValues(root: Optional[TreeNode]) -> List[int]:

	result = []
	if not root:
		return result

	queue = deque([root])
	while queue:
		level_size = len(queue)
		max_val = -math.inf

		for _ in range(level_size):
			________________________
			
			if node.left:
				queue.append(node.left)
			if node.right:
				queue.append(node.right)

		result.append(max_val)
	return result