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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _synthesize_single_python_helper( self, text, voice_code, output_file_path=None, return_audio_data=True ):
 """ This is an helper function to synthesize a single text fragment via a Python call. If ``output_file_path`` is ``None``, the audio data will not persist to file at the end of the method. :rtype: tuple (result, (duration, sample_rate, encoding, data)) """

        # return zero if text is the empty string
        if len(text) == 0:
            #
            # NOTE values of sample_rate, encoding, data
            #      do not matter if the duration is 0.000,
            #      so set them to None instead of the more precise:
            #      return (True, (TimeValue("0.000"), 16000, "pcm_s16le", numpy.array([])))
            #
            self.log(u"len(text) is zero: returning 0.000")
            return (True, (TimeValue("0.000"), None, None, None))

        #
        # NOTE in this example, we assume that the Speect voice data files
        #      are located in the same directory of this .py source file
        #      and that the voice JSON file is called "voice.json"
        #
        # NOTE the voice_code value is ignored in this example,
        #      since we have only one TTS voice,
        #      but in general one might select a voice file to load,
        #      depending on voice_code;
        #      in fact, we could have created the ``voice`` object
        #      only once, in the constructor, instead of creating it
        #      each time this function is invoked,
        #      achieving slightly faster synthesis
        #
        voice_json_path = gf.safe_str(gf.absolute_path("voice.json", __file__))
        voice = speect.SVoice(voice_json_path)
        utt = voice.synth(text)
        audio = utt.features["audio"]
        if output_file_path is None:
            self.log(u"output_file_path is None => not saving to file")
        else:
            self.log(u"output_file_path is not None => saving to file...")
            # NOTE apparently, save_riff needs the path to be a byte string
            audio.save_riff(gf.safe_str(output_file_path))
            self.log(u"output_file_path is not None => saving to file... done")

        # return immediately if returning audio data is not needed
        if not return_audio_data:
            self.log(u"return_audio_data is True => return immediately")
            return (True, None)

        # get length and data using speect Python API
        self.log(u"return_audio_data is True => read and return audio data")
        waveform = audio.get_audio_waveform()
        audio_sample_rate = int(waveform["samplerate"])
        audio_length = TimeValue(audio.num_samples() / audio_sample_rate)
        audio_format = "pcm16"
        audio_samples = numpy.fromstring(
            waveform["samples"],
            dtype=numpy.int16
        ).astype("float64") / 32768
        return (True, (
            audio_length,
            audio_sample_rate,
            audio_format,
            audio_samples
        ))