Python Бот Aiogram Помогите пожалйста

 while a == 0 :

    API_TOKEN = "7722868977:AAEDY6Rc5DdSTdI73YPeuqDjA94WLN1fcNU" 

    counter = 0

    a223 = 0

    now = datetime.now()

    bot = Bot(token=API_TOKEN) 

    dp = Dispatcher() 

    @dp.message(Command("start")) 
    async def send_welcome(message: types.Message): 
        await message.reply("Hi. \n My name is Printer! \n Printing... \n \n \n \n \n \n \n ERROR ERROR ERROR")
        now = datetime.now()
        User1 = message.from_user.id
        User2 = message.from_user.username
        print(now , "Someone use ur bot!!!\n\t\tUser ID:", User1, "\n\t\tNickname:", User2)

    @dp.message(Command("stop")) 
    async def stop_bot(message: types.Message):
        await message.answer("Бот остановлен.")
        a223 = a223 + 1

    async def main():
        await dp.start_polling(bot)

    if __name__ == '__main__':
        asyncio.run(main()) 

Нужно завершить цикл при присвоении переменной а223 возникает ошибка:
async def main():
^
UnboundLocalError: cannot access local variable 'a' where it is not associated with a value