current_users = ["Niuniu", "Niumei", "GURR", "LOLO"] new_users = ["GurR", "Niu Ke Le", "LoLo", "Tuo Rui Chi"] for i in new_users: po = i.upper() if po 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 na...