docs: def play(state):
          """ Play sound for a given state.
  
          :param state: a State value.
          """
          filename = None
          if state == SoundService.State.welcome:
              filename = "pad_glow_welcome1.wav"
          elif state == SoundService.State.goodbye:
              filename = "pad_glow_power_off.wav"
          elif state == SoundService.State.hotword_detected:
              filename = "pad_soft_on.wav"
          elif state == SoundService.State.asr_text_captured:
              filename = "pad_soft_off.wav"
          elif state == SoundService.State.error:
              filename = "music_marimba_error_chord_2x.wav"
  
          if filename is not None:
              AudioPlayer.play_async("{}/{}".format(ABS_SOUND_DIR, filename))