给定一棵二叉树，采用广度优先搜索 BFS 返回其右视图，其中右视图中的每个节点都是该层最右侧的节点。横线处应填写

from collections import deque

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

def rightSideView(root):
    result = []
    if not root:
        return result
    q = deque([root])
    while q:
        sz = len(q)
        for i in range(sz):
            node = q.popleft()
            __________________________
            if node.left:
                q.append(node.left)
            if node.right:
                q.append(node.right)
    return result