public function validateParentID($attribute)
    {
        if ($this->{$attribute} !== NULL)
        {
            $comment = self::find()->where(['id' => $this->{$attribute}, 'entity' => $this->entity, 'entityId' => $this->entityId])->active()->exists();
            if ($comment === FALSE)
            {
                $this->addError('content', Yii::t('app', 'Oops, something went wrong. Please try again later.'));
            }
        }
    }