def unknown(self):
        """
        Returns an utterance that tells the user the last input was not
        understood.
        """

        output = SPhraseSpec()
        output.setSubject('I')
        output.setComplement('you')
        output.setTense(Tense.PAST)

        choice = random.randint(1, 3)
        if choice == 1:
            output.setVerb('understand')
            output.setComplement('what you')
            output.setNegated(gateway.jvm.java.lang.Boolean.TRUE)
            output.setPostmodifier('just said')
        elif choice == 2:
            output.setInterrogative(InterrogativeType.WHAT)
            output.setVerb('do')
            output.setPostmodifier('say')
        elif choice == 3:
            output.setTense(Tense.PRESENT)
            output.setSubject('please rephrase')
            output.setComplement('what you')
            output.setPostmodifier('just said')

        return self.clean_str(REALISER.realiseDocument(output).strip())
    def unknown(self):
        """
        Returns an utterance that tells the user the last input was not
        understood.
        """

        output = SPhraseSpec()
        output.setSubject('I')
        output.setComplement('you')
        output.setTense(Tense.PAST)

        choice = random.randint(1, 3)
        if choice == 1:
            output.setVerb('understand')
            output.setComplement('what you')
            output.setNegated(gateway.jvm.java.lang.Boolean.TRUE)
            output.setPostmodifier('just said')
        elif choice == 2:
            output.setInterrogative(InterrogativeType.WHAT)
            output.setVerb('do')
            output.setPostmodifier('say')
        elif choice == 3:
            output.setTense(Tense.PRESENT)
            output.setSubject('please rephrase')
            output.setComplement('what you')
            output.setPostmodifier('just said')

        return REALISER.realiseDocument(output).strip()