用户登录验证

要求：
用户登录验证
用户依次输入用户名和密码，然后提交验证
用户不存在、密码错误，都显示用户名或密码错误提示
错误3次，则退出程序
验证成功则显示登录信息

user = 'root'
key = 'admin'
for i in range(3):
username=input('Please input username: ')
password = input('Please input password: ')
if username == user and password == key :
print('The user %s login success!'%(user))
break
elif i==2:
print('The number of password errors you have entered has reached the maximum, the account will be locked for 3 minutes')
else:
print("Username is not existed or password error!")

测试结果：

1. 正确输入用户名和密码：
   Please input username: root
   Please input password: admin
   The user root login success!

2. 连续输入错误3次：
   Please input username: root
   Please input password: root
   Username is not existed or password error!
   Please input username: root
   Please input password: hello
   Username is not existed or password error!
   Please input username: root
   Please input password: 123
   The number of password errors you have entered has reached the maximum, the account will be locked for 3 minutes