题解 | #禁止重复注册#

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