def METHOD_NAME(sequence, StartClass, raw_elems):
    """Assert a ReflowSequence has the defined structure."""
    assert [
        [seg.raw for seg in elem.segments] for elem in sequence.elements
    ] == raw_elems
    # We can assert all the classes just by knowing which we should start with
    assert all(type(elem) is StartClass for elem in sequence.elements[::2])
    OtherClass = ReflowBlock if StartClass is ReflowPoint else ReflowPoint
    assert all(type(elem) is OtherClass for elem in sequence.elements[1::2])