无法将文件发送到 aiogram3 python

我正在尝试使用以下方式发送.txt文件：

@router.message(Command(commands='test', prefix='!'))
async def abbreviatures(msg: Message):
    await msg.answer('text')
    with open('ab.txt', 'rb') as file:
        await msg.answer_document(file)

但它给出了这个错误：

ValidationError: 2 validation errors for SendDocument
document.is-instance[InputFile]
  Input should be an instance of InputFile [type=is_instance_of, input_value=<_io.BufferedReader name='ab.txt'>, input_type=BufferedReader]
    For further information visit https://errors.pydantic.dev/2.5/v/is_instance_of
document.str
  Input should be a valid string [type=string_type, input_value=<_io.BufferedReader name='ab.txt'>, input_type=BufferedReader]
    For further information visit https://errors.pydantic.dev/2.5/v/string_type
Traceback (most recent call last):
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\dispatcher.py", line 309, in _process_update
    response = await self.feed_update(bot, update, **kwargs)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\dispatcher.py", line 158, in feed_update
    response = await self.update.wrap_outer_middleware(
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\middlewares\error.py", line 25, in __call__
    return await handler(event, data)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\middlewares\user_context.py", line 27, in __call__
    return await handler(event, data)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\fsm\middleware.py", line 41, in __call__
    return await handler(event, data)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\event\telegram.py", line 121, in trigger
    return await wrapped_inner(event, kwargs)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\event\handler.py", line 43, in call
    return await wrapped()
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\dispatcher.py", line 276, in _listen_update
    return await self.propagate_event(update_type=update_type, event=event, **kwargs)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\router.py", line 128, in propagate_event
    return await observer.wrap_outer_middleware(_wrapped, event=event, data=kwargs)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\router.py", line 123, in _wrapped
    return await self._propagate_event(
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\router.py", line 156, in _propagate_event
    response = await router.propagate_event(update_type=update_type, event=event, **kwargs)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\router.py", line 128, in propagate_event
    return await observer.wrap_outer_middleware(_wrapped, event=event, data=kwargs)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\router.py", line 123, in _wrapped
    return await self._propagate_event(
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\router.py", line 148, in _propagate_event
    response = await observer.trigger(event, **kwargs)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\event\telegram.py", line 121, in trigger
    return await wrapped_inner(event, kwargs)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\dispatcher\event\handler.py", line 43, in call
    return await wrapped()
  File "C:\Users\Danil\Desktop\Bot translator\handlers.py", line 35, in abbreviatures
    await msg.answer_document(photo)
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\aiogram\types\message.py", line 1182, in answer_document
    return SendDocument(
  File "C:\Users\Danil\AppData\Local\Programs\Python\Python38\lib\site-packages\pydantic\main.py", line 164, in __init__
    __pydantic_self__.__pydantic_validator__.validate_python(data, self_instance=__pydantic_self__)
pydantic_core._pydantic_core.ValidationError: 2 validation errors for SendDocument
document.is-instance[InputFile]