public function getBalanceInfo($oauth_token, $sourceAccountId = [])
    {
        $corp_id = $this->settings['corp_id'];
        $apikey  = $this->settings['api_key'];
        $secret  = $this->settings['secret_key'];
        
        $this->validateArray($sourceAccountId);

        ksort($sourceAccountId);
        $arraySplit = implode(",", $sourceAccountId);
        $arraySplit = urlencode($arraySplit);

        $uriSign       = "GET:/banking/v3/corporates/$corp_id/accounts/$arraySplit";
        $isoTime       = self::generateIsoTime();
        $authSignature = self::generateSign($uriSign, $oauth_token, $secret, $isoTime, null);

        $headers                    = array();
        $headers['Accept']          = 'application/json';
        $headers['Content-Type']    = 'application/json';
        $headers['Authorization']   = "Bearer $oauth_token";
        $headers['X-BCA-Key']       = $apikey;
        $headers['X-BCA-Timestamp'] = $isoTime;
        $headers['X-BCA-Signature'] = $authSignature;

        $request_path = "banking/v3/corporates/$corp_id/accounts/$arraySplit";
        $domain       = $this->ddnDomain();
        $full_url     = $domain . $request_path;
        
        $data = array('grant_type' => 'client_credentials');

        \Unirest\Request::curlOpts(array(
            CURLOPT_SSL_VERIFYHOST => 0,
            CURLOPT_SSLVERSION => 6,
            CURLOPT_SSL_VERIFYPEER => false,
            CURLOPT_TIMEOUT => $this->settings['timeout'] !== 30 ? $this->settings['timeout'] : 30
        ));

        $body     = \Unirest\Request\Body::form($data);
        $response = \Unirest\Request::get($full_url, $headers, $body);

        return $response;
    }