public function check($transactionId) {
        return $this->sendRequest(
            function () use ($transactionId) {
                $uri = Constants::API_VERSION_ROUTE . '/requests/' . $transactionId . self::CHECK_API;
                return $this->guzzle->get($uri, [
                    'headers' => $this->getRequestAuthHeaders($uri),
                ]);
            },
            $transactionId
        );
    }