python登陆，注册小程序

 def login(username,password):
     '''
     用于用户登录
     :param username: 用户输入用户名
     :param password: 用户输入密码
     :return: True表示登陆成功
     '''
     f = open("db","r")
     for line in f:#一行一行检测
         line_list = line.strip().split("|")
         if line_list[0] == username and line_list[1]  == password:
             return True

 def register(username,password):
     '''
     用户注册
     :param username: 用户名
     :param password: 密码
     :return: 默认返回None
     '''
     f = open("db", "a")
     temp = "\n" + username + "|" +password
     f.write(temp)
     f.close()

 def main():
     t = input("1:登陆 2:注册")
     if t == "":
         user = input("请输入用户名:")
         pwd = input("请输入密码:")
         r = login(user,pwd)
         if r:
             print("登陆成功")
         else:
             print("登陆失败")
     elif t == '':
         user = input("请输入用户名:")
         pwd = input("请输入密码:")
         register(user,pwd)
 main()