#Author:zhanghonglincounter = 0#确定真实用户名和密码real_name = "itssky"real_password = "itssoft"#读取黑名单f = open("black_user","r")lock_file = f.read()f.close()user_name = input("请输入您的用户名：")#判定是否是黑名单用户for i in range(1):    if user_name == lock_file:        print("对不起，你的账户被锁定，无法登陆!")        exit()    else:        continue#判定登陆次数for i in range(3):    password = input("请输入您的密码:")    if password == real_password:        print("登陆成功！")        break    else:        print("登陆失败！")        counter +=1if counter == 3:    print("对不起！您的错误输入已达三次，即将锁定账户。")    f = open("black_user","w")    f.write("%s"%user_name)    f.close()