题解 | #禁止重复注册#

current_users = ['Niuniu','Niumei','GURR','LOLO']
new_users = ['GurR','Niu Ke Le','LoLo','Tuo Rui Chi']
for i in new_users:
    if i.upper() in [current_user.upper() for current_user in current_users]:
        print(f'The user name {i} has already been registered! Please change it and try again!')
    else:
        print(f'Congratulations, the user name {i} is available!')