写代码：用户交互显示类似省市县三级联动的选择

仍然需要修改：

# encoding: utf-8
# 用户交互显示类似省市县N级联动的选择
# * 允许用户增加内容
# * 允许用户查看某一个级别内容

dic = {
    "江西": {
        "萍乡": ["安源", "彭高", "上栗"],
        "新余": ["良山", "新钢", "兴安岭"],
    },
    "北京": {
        "大兴区": ["礼贤镇", "魏善庄镇", "北臧村镇"],
        "昌平区": ["沙河", "化庄", "白浮泉"],
    },
    "福建": {
        "莆田": ["荔城", "西天尾", "九化山"],
        "厦门": ["湖里", "思明", "海仓"],
    }
}
print("目前可查询的省份：江西、北京、福建")
province = input("请输入省份或者输入N新建： ")

if province == "N":
    new_province = input("请输入省份：")
    new_city = input("请输入城市：")
    new_town = input("请输入城镇信息：")
    dic[new_province] = {new_city: [new_town]}

while province not in dic:
    print("输入错误省份，请从新输入")
    province = input("请输入省份或者输入N新建： ")

while province in dic:
    new_menu = dic[province]
    for k in new_menu:
        print(k, end="
")
    choice_city = input("请输入城市：")
    if choice_city not in new_menu:
        print("错误城市输入，请从新输入： ")
        continue
    else:
        new_menu2 = new_menu.get(choice_city)
        for i in new_menu2:
            print(i, end="
")
        choice_town = input("请输入城镇信息：")
        if choice_town in new_menu2:
            print(
                "信息输入正确，省份：{}，城市：{}，城镇：{}".format(
                    province,
                    choice_city,
                    choice_town))
            break