public function fetchRefund($refundId)
    {
        if ($this->offsetExists('refunds')) {
            foreach ($this['refunds'] as $refund) {
                if ($refund->getId() !== $refundId) {
                    continue;
                }

                return $refund;
            }
        }

        $refund = new Refund($this->connector, $this->getLocation(), $refundId);
        $refund->fetch();

        $this['refunds'][] = $refund;

        return $refund;
    }