public function getSubscriptions($subscriber_id = null)
{
/** @var $query \yii\db\ActiveQuery */
$query = models\DbSubscription::find()->current()->withQueue($this->id)->with(['categories']);
if ($subscriber_id !== null) {
$dbSubscriptions = $query->andWhere('subscriber_id=:subscriber_id', [':subscriber_id' => $subscriber_id]);
}
$dbSubscriptions = $query->all();
return models\DbSubscription::createSubscriptions($dbSubscriptions);
}