写一个登陆和注册用户的程序

def login(username,password):
    '''
    用于用户登陆
    :param username:  登陆的用户名
    :param password:  登陆的密码
    :return:          返回true，登陆成功，返回false，登陆失败
    '''
    f = open('db','r')
    for line in f:
        line_list = line.strip().split('|')
        if line_list[0] == username and line_list[1] == password:
            return True
    else:
        return False


def register(username,password):
    '''
    
    :param username: 注册的用户名
    :param password: 注册的密码
    :return: 
    '''
    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 == '1':
        username = input("Input username:")
        password = input("Input password:")
        ret = login(username,password)
        if ret == True:
            print("登陆成功")
        else:
            print("登陆失败")
    else:
        username = input("Input username:")
        password = input("Input password:")
        register(username,password)


main()