Trims the output speech if it already has the
        <speak></speak> tag.

        :param speech_output: the output speech sent back to user.
        :type speech_output: str
        :return: the trimmed output speech.
        :rtype: Union[bool, None]

def __trim_outputspeech(self, speech_output=None):
        # type: (Union[str, None]) -> str
        """Trims the output speech if it already has the
        <speak></speak> tag.

        :param speech_output: the output speech sent back to user.
        :type speech_output: str
        :return: the trimmed output speech.
        :rtype: Union[bool, None]
        """
        if speech_output is None:
            return ""
        speech = speech_output.strip()
        if speech.startswith("<speak>") and speech.endswith("</speak>"):
            return speech[7:-8].strip()
        return speech