public function getSignatureRequests($page = 1)
    {
        $params = array(
            'page' => $page
        );

        $response = $this->rest->get(
            static::SIGNATURE_REQUEST_LIST_PATH,
            $params
        );

        $this->checkResponse($response);

        $list = new SignatureRequestList($response);

        if ($page > $list->getNumPages()) {
            throw new Error('page_not_found', 'Page not found');
        }

        return $list;
    }