public static function validateSubject($subject, $throwException = true)
	{
		if (!ComponentConfig::isActiveRecord($subject, $throwException)) return false;
		if (!ComponentConfig::hasBehavior($subject, CommentsBehavior::className(), $throwException)) return false;

		if (empty($subject->primaryKey) || (is_array($subject->primaryKey) && count($subject->primaryKey) === 0)) {
			if (!$throwException) return false;
			$msg = Yii::t('app', 'The model needs a valid primary key');
			throw new InvalidParamException($msg);
		}

		if ($subject->isNewRecord) {
			if (!$throwException) return false;
			$msg = Yii::t('app', 'Commenting is not possible on unsaved models');
			throw new InvalidParamException($msg);
		}

		return true;
	}