Supplier/EventListener/SupplierOrderListener.php
protected function getSupplierOrderFromEvent(ResourceEventInterface $event)
    {
        $order = $event->getResource();

        if (!$order instanceof SupplierOrderInterface) {
            throw new InvalidArgumentException("Expected instance of SupplierOrderInterface.");
        }

        return $order;
    }
protected function getSupplierOrderFromEvent(ResourceEventInterface $event)
    {
        $order = $event->getResource();

        if (!$order instanceof SupplierOrderInterface) {
            throw new InvalidArgumentException("Expected instance of SupplierOrderInterface.");
        }

        return $order;
    }
Returns the supplier order from the event.

@param ResourceEventInterface $event

@return SupplierOrderInterface
@throws InvalidArgumentException