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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 _prepare_audio(self, basename, replace_already_indexed=False):
 """ Prepares and stages the audio file to be indexed. Parameters basename : str, None A basename of `/home/random-guy/some-audio-file.wav` is `some-audio-file.wav` If basename is `None`, it'll prepare all the audio files. """

        if basename is not None:
            if basename in self.get_timestamps():
                if self.get_verbosity():
                    print("File specified was already indexed. Reindexing...")
                del self.__timestamps[basename]
            self._filtering_step(basename)
            self._staging_step(basename)
        else:
            for audio_basename in self._list_audio_files():
                if audio_basename in self.__timestamps:
                    if replace_already_indexed:
                        if self.get_verbosity():
                            print("Already indexed {}. Reindexing...".format(
                                audio_basename))
                        del self.__timestamps[audio_basename]
                    else:
                        if self.get_verbosity():
                            print("Already indexed {}. Skipping...".format(
                                audio_basename))
                        continue
                self._filtering_step(audio_basename)
                self._staging_step(audio_basename)