RestClient::post PHP Method

    public function post($url, $parameters = [], $headers = [])
    {
        return $this->execute($url, 'POST', $parameters, $headers);
    }

 function createApp($appName, $orgName)
 {
     Util::throwExceptionIfNullOrBlank($appName, "App Name");
     Util::throwExceptionIfNullOrBlank($orgName, "orgName");
     $objUtil = new Util($this->apiKey, $this->secretKey);
     try {
         $params = array();
         $params['apiKey'] = $this->apiKey;
         $params['version'] = $this->version;
         date_default_timezone_set('UTC');
         $params['timeStamp'] = date("Y-m-d\\TG:i:s") . substr((string) microtime(), 1, 4) . "Z";
         $params['App Name'] = $appName;
         $params['orgName'] = $orgName;
         $signature = urlencode($objUtil->sign($params));
         //die();
         $body = null;
         $body = '{"app42":{"app":}}';
         $params['body'] = $body;
         $params['signature'] = $signature;
         $contentType = $this->content_type;
         $accept = $this->accept;
         $this->url = $this->url;
         $response = RestClient::post($this->url, $params, null, null, $contentType, $accept, $body);
     } catch (App42Exception $e) {
         throw $e;
     } catch (Exception $e) {
         throw new App42Exception($e);
     }
     return $response;
 }