Python--输入用户名密码，认证成功后显示欢迎信息，输错三次后锁定

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:Huanglinsheng
#输入用户名密码，认证成功后显示欢迎信息，输错三次后锁定

file = open('lock.txt').readlines()
name = input('username:').strip()
lock=[]
for i in file:
     line = i.strip('\n')
     lock.append(line)
if name in lock:
     print(name,'已经被锁定,请联系开户行.退出!')
else:
     i = 1
     while i <=3:
            i = i + 1
            print('........................')
            username = name
            print (username)
            passwd = input('Passwd:').strip()
            f = open('user.txt', 'r')
            login = False
            if len(username) != 0 and len(passwd) != 0:
                  for line in f.readlines():
                        if username == line.split()[0] and passwd == line.split()[1] :
                              print("欢迎中国银行AMT系统")
                              login = True
                              break
                        else:
                              continue
            if login is True:
                              break
     else:
            f = open('lock.txt', 'a')
            f.write(name)
            f.write('\n')
            f.close()
            print(name,'你的密码输入超过三,锁定帐号,退出')