python 简单用户登录操作

import  sys
#被锁住用户
locked_name_list = {"zhangsan","lisi"}
#正常用户
mtch_name_list = {"wangwu":"123456","maliu":"123456"}
#输入匹配次数
match_count = 0
#允许输入的次数
match_limit = 3
while match_count < match_limit:
    flag = False
    user_name = input("请输入的用户名：")
    if len(user_name) == 0:
        print("用户名不为空!")
        continue
    for lock_name in locked_name_list:
        if lock_name == user_name:
            print("该用户被锁定!")
            break
        user_password = input("请输入密码：")
        for (match_name,match_password) in mtch_name_list.items():
            if len(match_name) == 0:
                print("该系统还未有用户！")
                exit();
            if match_name == user_name and match_password == user_password:
                print("欢迎登陆该系统!")
                exit()
            if match_name and match_password != user_password:
                if match_count < 2:
                    match_count += 1
                    print("密码输入错误，请重新输入！")
                    break
                else:
                    print("登陆次数超过三次，该用户被锁定！")
                    exit()