题解 | #禁止重复注册#

import sys

current_users = ['Niuniu','Niumei','GURR', 'LOLO']
new_users = ['GurR','Niu Ke Le','LoLo','Tuo Rui Chi']


current_users_upper = []
for user in current_users:
    current_users_upper.append(user.upper())


for user in new_users:
    if user.upper() in current_users_upper:
        print('The user name %s has already been registered! Please change it and try again!' % user)
    else:
        print('Congratulations, the user name %s is available!' % user)