python小练习-实现三级菜单

#三级菜单字典
district = {
            "shanxi":{
                "xian":{"huxian":1,"baqiao":2},
                "hanzhong":{"yangxian":3,"chengu":4,"xixiang":5},
                "baoji":{"qishan":6,"fufeng":7,"meixian":8},
                },
            "guangdong":{
                "shenzhen":{"A":9,"B":10,"C":11},
                "guangzhou":{"E":12,"F":13,"G":14},
                "huizhou":{"X":15,"Y":16,"Z":17}
                }

#递归实现三级菜单
def menu(all_menu):
    while True:
        for sub_menu in all_menu:
            print sub_menu,":"
        choose = raw_input("please choose menu：")
        if choose in all_menu and isinstance(all_menu[choose],Iterable):
            menu(all_menu[choose])
        elif choose == "b":
            break
        elif choose == "q":
            exit()

#使用嵌套循环实现三级菜单
while True:
    for first in district:
        print first,":"
    choose1 = raw_input("please choose menu1：")
    if choose1 in district:
        while True:
            for second in district.get(choose1):
                print second,":"
            choose2 = raw_input("please choose menu2:")
            if choose2 in district.get(choose1):
                while True:
                    for third in district.get(choose1).get(choose2):
                        print third
                    choose3 = raw_input("please choose menu3:")
                    if choose3 in district.get(choose1).get(choose2):
                        pass
                    elif choose3 == "b":
                        break
                    elif choose3 == "q":
                        exit()
            elif choose2 == "b":
                break

            elif choose2 == "q":
                exit()
    elif choose1 == "q":
        exit()