code: public int getSoundVolume() throws CommandExecutionException {
          JSONArray res = sendToArray("get_sound_volume");
          if (res == null) throw new CommandExecutionException(CommandExecutionException.Error.INVALID_RESPONSE);
          int vol = res.optInt(0, -1);
          if (vol < 0) throw new CommandExecutionException(CommandExecutionException.Error.INVALID_RESPONSE);
          return vol;
      }
docs: Get the current volume.
  @return The current set volume of the device between 0 and 100.
  @throws CommandExecutionException When there has been a error during the communication or the response was invalid.