public function setAvailablePostage($country, $code)
    {
        $postage_areas = new ShippingCalculator($code, $country);
        
        $postage_areas
            ->setCost($this->SubTotalCost)
            ->setWeight($this->TotalWeight)
            ->setItems($this->TotalItems);
            
        $postage_areas = $postage_areas->getPostageAreas();
        
        Session::set("Checkout.AvailablePostage", $postage_areas);

        return $this;
    }