public static function getTopic(Core $core, $id)
 {
     $url = self::getUrl($core) . Topic::generateUrn($core, $id);
     $response = Client::GET($url, self::getHeaders($core));
     $body = self::getDataFromResponse($response);
     if (!property_exists($body, "topic")) {
         return null;
     }
     return Topic::serializeFromJson($body->{"topic"});
 }