字典层级新建

db = {}
path = []
while True:
    temp = db
    for item in path:
        temp = temp[item]
    print('当前节点的所有可选子节点：',list(temp.keys()),'\n')
    choice = input("1:添加节点；2:查看节点(Q退出/B返回上一级) \n>>>")
    if choice == "1":
        k = input("请输入要添加的节点名称：")
        if k in temp.keys():
            print("节点已经存在")
        else:
            temp[k] = {}
    elif choice == "2":
        k = input("请输入查看的子节点：")
        if k in temp:
            path.append(k)
        else:
            print("子节点名称有误")
    elif choice.lower() == 'b':
        if path:
            path.pop()
    elif choice.lower() == 'q':
        break
    else:
        print("输入不合法")