public function sortDeliveries(): self
    {
        $this->sort(function (Delivery $a, Delivery $b) {
            if ($a->getLocation() !== $b->getLocation()) {
                return -1;
            }

            return $a->getDeliveryDate()->getEarliest() > $b->getDeliveryDate()->getEarliest();
        });

        return $this;
    }