src/ORM/OrderItemList.php
public function SubTotal()
    {
        $result = 0;
        foreach ($this->getIterator() as $item) {
            $result += $item->Total();
        }

        return $result;
    }
public function SubTotal()
    {
        $result = 0;
        foreach ($this->getIterator() as $item) {
            $result += $item->Total();
        }

        return $result;
    }
Add up the totals of all the order items in this list.