Python判断登录

import datetime
today=datetime.date.today()
username="iris"
passwd="haha"
write="%s欢迎登录，今天的日期是%s"%(username,today)
for i in range(3):
    i_username=input("请输入用户名：")
    if i_username=="" or i_username.isspace():
        print("不能为空")
        continue
    i_passwd=input("请输入密码：")
    if i_username!=username:
        print("用户名错误")
    elif i_passwd!=passwd:
        print("密码错误")
    else:
        print(write)
        break
else:
    print("次数过多")