python3.5------用户的三次验证

#/usr/bin/python
# -*- coding: utf-8 -*-

lock = open("black_user_list.txt", ‘a‘, encoding=‘utf-8‘)
lock.write("\n")
user_list = open("userlist.txt", ‘w+‘, encoding=‘utf-8‘)
user_list.write("zhangsan\n")
user_list.write("lisi\n")
user_list.close()
user_list = open("userlist.txt", ‘r‘, encoding=‘utf-8‘)
white_username = user_list.read().strip()
user_list.close()
lock = open("black_user_list.txt", ‘r+‘, encoding=‘utf-8‘)
lock_username = lock.read().strip()
while True:
    username = input("username:")
    if username in lock_username:
        print("\033[31;1m %s Account lockout \033[0m" % username)
        break
    elif username in white_username:
        for i in range(2, -1, -1):
            password = input("password:")
            if password == ‘abc123‘:
                print("Welcome to log on %s" % username)
                break
            else:
                print("\033[31;1mPassword remaining: \033[0m %s" % i)
                if i == 0:
                    print("\033[31;1m %s Account lockout \033[0m" % username)
                    lock.write("\n")
                    lock.write(username)
                    lock.close()
                    exit()
    else:
        print("Account does not exist")