def METHOD_NAME():
    learner = LStar(lambda s: len(s) == 4 and max(s) <= 1)
    learner.learn(bytes(4))
    assert learner.dfa.matches(bytes(4))
    assert learner.dfa.matches(bytes([1] * 4))
    assert learner.dfa.matches(bytes([1] * 4))
    learner.learn([2, 0, 0, 0])
    # Need a length 5 string to distinguish this from
    # something that just loops back to zero.
    learner.learn([2, 0, 0, 0, 0])
    dfa = learner.dfa
    assert dfa.is_dead(dfa.transition(dfa.start, 2))
    assert dfa.is_dead(dfa.transition(dfa.start, 3))