判断是不是完全二叉树

to debug:

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param root TreeNode类 
# @return bool布尔型
#
from typing import Tuple
class Solution:
    def isCompleteTree(self , root: TreeNode) -> bool:
        depth = 1
        choices = [root]
        
        def next_loop(choices:List[TreeNode])->Tuple[List[TreeNode],bool]:
            new_choices = []
            null_leaves = 0
            for choice in choices:
                if choice.left is not None:
                    if null_leaves==0:
                        new_choices.append(choice.left)
                    else:
                        return [],False
                else:
                    null_leaves+=1
                if choice.right is not None:
                    if null_leaves==0:
                        new_choices.append(choice.right)
                    else:
                        return [],False
                else:
                    null_leaves+=1
                print(new_choices)
            return new_choices,True

        while len(choices)!=0:
            new_choices,not_all_left = next_loop(choices)
            if (not not_all_left):
                return False
            if len(new_choices)!=0 and len(new_choices)!=2**(depth-1):
                return False
            depth+=1
            choices = new_choices
        return True