def METHOD_NAME(self):
    """
    L{None} does not appear in the sentence attributes of the
    protocol, even though it's in the specification.
    This is because L{None} is a placeholder for parts of the sentence you
    don't really need or want, but there are some bits later on in the
    sentence that you do want. The alternative would be to have to specify
    things like "_UNUSED0", "_UNUSED1"... which would end up cluttering
    the sentence data and eventually adapter state.
    """
    sentenceAttributes = self.protocol.getSentenceAttributes()
    self.assertNotIn(None, sentenceAttributes)
    sentenceContents = self.protocol._SENTENCE_CONTENTS
    sentenceSpecAttributes = itertools.chain(*sentenceContents.values())
    self.assertIn(None, sentenceSpecAttributes)