def METHOD_NAME(self):
    router = Router()
    assert isinstance(router.message._handler.filters, list)
    assert not router.message._handler.filters
    my_filter = MyFilter1(test="pass")
    router.message.filter(my_filter)
    assert len(router.message._handler.filters) == 1
    assert router.message._handler.filters[0].callback is my_filter
    router.message._handler.filters = None
    router.message.filter(my_filter)
    assert len(router.message._handler.filters) == 1
    assert router.message._handler.filters[0].callback is my_filter