leetcode-199题:binary tree right side view

def rightSideView(self, root):
    """
    :type root: TreeNode
    :rtype: List[int]
    """
    result = []
    if root == None:
        return result
    queue = [root,'#']
    tag = True
    while len(queue) != 1:
        node = queue[0]
        queue.remove(node)
        if node == '#':
            tag = True
            queue.append('#')
        else:
            if node.right != None:
                queue.append(node.right)
            if node.left != None:
                queue.append(node.left)
            if tag:
                result.append(node.val)
                tag = False
    return result