docs: def _index_audio_cmu(self, basename=None, replace_already_indexed=False):
          """
          Indexes audio with pocketsphinx. Beware that the output would not be
          sufficiently accurate. Use this only if you don't want to upload your
          files to IBM.
  
          Parameters
          -----------
          basename : str, optional
              A specific basename to be indexed and is placed in src_dir
              E.g. `audio.wav`.
  
              If `None` is selected, all the valid audio files would be indexed.
              Default is `None`.
  
          Raises
          ------
          OSError
              If the output of pocketsphinx command results in an error.
          """
          self._prepare_audio(basename=basename,
                              replace_already_indexed=replace_already_indexed)
  
          for staging_audio_basename in self._list_audio_files(
                  sub_dir="staging"):
              original_audio_name = ''.join(
                  staging_audio_basename.split('.')[:-1])[:-3]
              pocketsphinx_command = ''.join([
                  "pocketsphinx_continuous", "-infile",
                  str("{}/staging/{}".format(
                      self.src_dir, staging_audio_basename)),
                  "-time", "yes", "-logfn", "/dev/null"])
              try:
                  if self.get_verbosity():
                      print("Now indexing {}".format(staging_audio_basename))
                  output = subprocess.check_output([
                      "pocketsphinx_continuous", "-infile",
                      str("{}/staging/{}".format(
                          self.src_dir, staging_audio_basename)),
                      "-time", "yes", "-logfn", "/dev/null"
                  ], universal_newlines=True).split('\n')
                  str_timestamps_with_sil_conf = list(map(
                      lambda x: x.split(" "), filter(None, output[1:])))
                  # Timestamps are putted in a list of a single element. To match
                  # Watson's output.
                  self.__timestamps_unregulated[
                      original_audio_name + ".wav"] = [(
                          self._timestamp_extractor_cmu(
                              staging_audio_basename,
                              str_timestamps_with_sil_conf))]
                  if self.get_verbosity():
                      print("Done indexing {}".format(staging_audio_basename))
              except OSError as e:
                  if self.get_verbosity():
                      print(e, "The command was: {}".format(
                          pocketsphinx_command))
                  self.__errors[(time(), staging_audio_basename)] = e
          self._timestamp_regulator()
  
          if self.get_verbosity():
              print("Finished indexing procedure")