def METHOD_NAME(demoinfo: DemoInfo):
    demoinfo.add_demo(demo_id, demo_title, state).unwrap()
    with open(demo_extras_file, "rb") as demo_extras:
        demo_extras_name = os.path.basename(demo_extras.name)
        demoinfo.add_demoextras(demo_id, demo_extras.read(), demo_extras_name).unwrap()
        extras_name = demo_extras.name
    result = demoinfo.get_demo_extras_info(demo_id)
    info = result.unwrap()
    assert info is not None
    assert info["size"] == os.stat(extras_name).st_size