code: def _update_length(self):
          
          if (self.audio_sample_rate is not None) and (self.__samples is not None):
              # NOTE computing TimeValue (... / ...) yields wrong results,
              #      see issue #168
              #      self.audio_length = TimeValue(self.__samples_length / self.audio_sample_rate)
              self.audio_length = TimeValue(self.__samples_length) / TimeValue(self.audio_sample_rate)
docs: Update the audio length property,
          according to the length of the current audio data
          and audio sample rate.
  
          This function fails silently if one of the two is ``None``.