private function getToken()
    {
        $data = array(
            'grant_type' => 'client_credentials',
            'client_id' => $this->userId,
            'client_secret' => $this->secret,
        );

        $requestResult = $this->sendRequest('oauth/access_token', 'POST', $data, false);

        if ($requestResult->http_code !== 200) {
            return false;
        }

        $this->refreshToken = 0;
        $this->token = $requestResult->data->access_token;

        $hashName = md5($this->userId . '::' . $this->secret);
        /** Save token to storage */
        $this->tokenStorage->set($hashName, $this->token);

        return true;
    }