使用json存储数据

import jsondef get_stored_username(): ???"""如果获取了用户名，就获取她""" ???filename = ‘username.json‘ ???try: ???????with open(filename) as file_obj: ???????????username = json.load(file_obj) ???except FileNotFoundError: ???????return None ???else: ???????return usernamedef get_new_username(): ???"""提示用户输入用户名""" ???filename = ‘username.json‘ ???username = input("Please input your name\n") ???with open(filename,‘w‘) as file_obj: ???????json.dump(username,file_obj) ???????"""写入数据，从左写入右""" ???return usernamedef greet_user(): ???"""问候用户""" ???username = get_stored_username() ???if username: ???????print(username + " ?Welcome back\n") ???else: ???????username = get_new_username()greet_user()