/** * @param Ess_M2ePro_Model_Order_Item_Proxy[] $items * @return Ess_M2ePro_Model_Order_Item_Proxy[] * @throws Exception */ protected function mergeItems(array $items) { foreach ($items as $key => $item) { if ($item->getPrice() <= 0) { unset($items[$key]); } } if (count($items) == 0) { throw new Exception('Every item in order has zero price.'); } return parent::mergeItems($items); }