code: def _timestamp_extractor_cmu(self, staging_audio_basename,
                                   str_timestamps_with_sil_conf):
          
          filter_untimed = filter(lambda x: len(x) == 4,
                                  str_timestamps_with_sil_conf)
          if filter_untimed != str_timestamps_with_sil_conf:
              self.__errors[
                  (time(), staging_audio_basename)
              ] = str_timestamps_with_sil_conf
          str_timestamps = [
              str_timestamp[:-1]
              for str_timestamp in filter_untimed
              if not any([letter in {"<", ">", "/"}
                          for letter in ''.join(str_timestamp)])]
          timestamps = list([
              _WordBlock(
                  word=re.findall("^[^\(]+", x[0])[0],
                  start=round(float(x[1]), 2),
                  end=round(float(x[2]), 2)
              ) for x in str_timestamps])
          return timestamps
docs: Parameters
          ----------
          str_timestamps_with_sil_conf : [[str, str, str, str]]
              Of the form [[word, starting_sec, ending_sec, confidence]]
  
          Returns
          -------
          timestamps : [[str, float, float]]