work01-2 三级菜单（数据保存在文件中）

json
f=(,  =)
ChinaMap = json.load(f)

welcome_msg = end_msg = .center(,)
menu_one = .center(,)
menu_two = .center(,)
menu_three = .center(,)
menu_select = one_menu():
province_dict  province  area_list = []
i ChinaMap:  i (i.keys()): area_list.append(i[])    :
(menu_one) i (area_list):  (i[], i[])     select_area_id = ()
select_area_id == :     ()    :
select_area_id.isdigit():   select_area_id = (select_area_id)    select_area_id >= (area_list):     ()
:
:
()

select_area_dict = ChinaMap[select_area_id] k select_area_dict:
province_dict = select_area_dict[k]
province = province_dict.keys()

one_menu()
two_menu():
city_list

:
(menu_two)
province_list = []
k (province):
province_list.append(k[])
(k[], k[])
select_provice_id = (menu_select)

select_provice_id == :
()
select_provice_id == :
one_menu()
:
select_provice_id.isdigit():
select_provice_id = (select_provice_id)
select_provice_id >= (province_list):
()
:
:
()
select_provice = province_list[select_provice_id]
city_list = province_dict[select_provice]

three_menu():
two_menu()
:
(menu_three)
i (city_list):
(i[], i[])

select_city_id = (menu_select)
select_city_id == :
()
select_city_id == :
two_menu()
:
select_city_id.isdigit():
select_city_id = (select_city_id)
select_city_id >= (city_list):
()
:
:
()

city = city_list[select_city_id]
(end_msg %city)

three_menu()