public function setReplayGain($replayGain)
	{
		$values = [self::REPLAY_GAIN_DROP, self::REPLAY_GAIN_IGNORE, self::REPLAY_GAIN_TRACK, self::REPLAY_GAIN_ALBUM];
		
		if ( ! is_scalar($replayGain) || ! in_array($replayGain, $values, false))
		{
			throw new \InvalidArgumentException(sprintf('Wrong replayGain value for %s, available values are %s',
				(string) $replayGain, implode(', ', $values)));
		}
		
		$this->replayGain = (string) $replayGain;
		
		return $this;
	}