Helper::getDeltaInterval

public function getDeltaInterval(): array
{
	if (empty(static::$deltaInterval))
	{
		$from = new Date();
		$from->getDate()->add(self::DELTA_INTERVAL['from']);
		$to = new Date();
		$to->getDate()->add(self::DELTA_INTERVAL['to']);
		static::$deltaInterval = [
			'from' => $from,
			'to' =>$to
		];
	}

	return static::$deltaInterval;
}