def METHOD_NAME():
    sf = zb.split_frame()
    assert len(sf) == 0
    assert len(sf.past) == 0
    assert len(sf.future) == 0
    sf = zb.split_frame(past={"x": [1, 2, 3]})
    assert len(sf) == 3
    assert len(sf.past) == 3
    assert len(sf.future) == 0
    sf = zb.split_frame(future={"x": [1, 2, 3]})
    assert len(sf) == 3
    assert len(sf.past) == 0
    assert len(sf.future) == 3