Python自动化开发—EX.2(三级菜单)

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Author:DaShuang.Gu
#三级菜单
data = {
    '北京':{
        "昌平":{
            "沙河":["oldboy","test"],
            "天通苑":["链家地产","我爱我家"]
        },
        "朝阳":{
            "望京":["奔驰","陌陌"],
            "国贸":{"CICC","HP"},
            "东直门":{"Advent","飞信"},
        },
        "海淀":{},
    },
    '山东':{
        "德州":{},
        "青岛":{},
        "济南":{}
    },
    '广东':{
        "东莞":{},
        "常熟":{},
        "佛山":{},
    },
}
flag = True
while flag:
    for L in data:
        print(L)
    choice1 = input("选择进入1>>:")
    if choice1 in data:
        while flag:
            for L1 in data[choice1]:
                print('\t',L1)
            choice2 = input("选择进入2>>:")
            if choice2 in data[choice1][choice2]:
                while flag:
                    for L2 in data[choice1][choice2]:
                        print('\t\t', L2)
                    choice3 = input("选择进入3>>")
                    if choice3 in data[choice1][choice2][choice3]:
                        while flag:
                            for L3 in data[choice1][choice2][choice3]:
                                print('\t\t\t',L3)
                            choice4 = input("最后一层按b返回>>：")
                            if choice4 =="b":
                                break
                            elif choice4 == "q":
                                flag = False
                    if choice3 =="b":
                        break
                    elif choice3 == "q":
                        flag = False
            if choice2 == "b":
                break
            elif choice2 == "q":
                flag = False