def METHOD_NAME(loader_factory):
    loader = loader_factory(get_dataset(), 1.0, 1.5)
    d = next(iter(loader))
    field_names = [
        "past_target",
        "past_valid_length",
        "future_target",
        "future_valid_length",
    ]
    assert all([key in d for key in field_names])
    assert d["past_target"].shape[2] == d["future_target"].shape[2] == 2
    assert d["past_target"].shape[0] == d["future_target"].shape[0] == 10
    assert (
        d["past_valid_length"].shape[0]
        == d["future_valid_length"].shape[0]
        == 10
    )