def METHOD_NAME(
    schedule_item_factory,
    submission_factory,
    conference_factory,
    schedule_item_additional_speaker_factory,
):
    schedule_item_1 = schedule_item_factory(
        type="talk", submission=submission_factory(speaker_id=1)
    )
    schedule_item_2 = schedule_item_factory(
        type="talk",
        conference=schedule_item_1.conference,
        submission=submission_factory(speaker_id=2),
    )
    schedule_item_3 = schedule_item_factory(
        type="talk",
        conference=schedule_item_1.conference,
        submission=submission_factory(speaker_id=3),
    )
    schedule_item_3.additional_speakers.add(
        schedule_item_additional_speaker_factory(user_id=10)
    )
    schedule_item_different_conf = schedule_item_factory(
        type="talk",
        conference=conference_factory(),
        submission=submission_factory(speaker_id=9999),
    )
    speaker_ids = speakers_user_ids(schedule_item_1.conference)
    assert len(speaker_ids) == 4
    assert schedule_item_1.submission.speaker_id in speaker_ids
    assert schedule_item_2.submission.speaker_id in speaker_ids
    assert schedule_item_3.submission.speaker_id in speaker_ids
    assert 10 in speaker_ids
    assert schedule_item_different_conf.submission.speaker_id not in speaker_ids