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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 _clear_audio_file(self, audio_file):
 """ Clear audio from memory. :param audio_file: the object to clear :type audio_file: :class:`~aeneas.audiofile.AudioFile` """

        self._step_begin(u"clear audio file")
        audio_file.clear_data()
        audio_file = None
        self._step_end()