code: def _extract_mfcc(self, file_path=None, file_format=None, audio_file=None):
          
          audio_file_mfcc = AudioFileMFCC(
              file_path=file_path,
              file_format=file_format,
              audio_file=audio_file,
              rconf=self.rconf,
              logger=self.logger
          )
          if self.rconf.mmn:
              self.log(u"Running VAD inside _extract_mfcc...")
              audio_file_mfcc.run_vad(
                  log_energy_threshold=self.rconf[RuntimeConfiguration.MFCC_MASK_LOG_ENERGY_THRESHOLD],
                  min_nonspeech_length=self.rconf[RuntimeConfiguration.MFCC_MASK_MIN_NONSPEECH_LENGTH],
                  extend_before=self.rconf[RuntimeConfiguration.MFCC_MASK_EXTEND_SPEECH_INTERVAL_BEFORE],
                  extend_after=self.rconf[RuntimeConfiguration.MFCC_MASK_EXTEND_SPEECH_INTERVAL_AFTER]
              )
              self.log(u"Running VAD inside _extract_mfcc... done")
          return audio_file_mfcc
docs: Extract the MFCCs from the given audio file.
  
          :rtype: :class:`~aeneas.audiofilemfcc.AudioFileMFCC`