code: public static function createFault($code, $message)
      {
          $response = new \SimpleXMLElement("<methodResponse></methodResponse>");
          $struct = $response->addChild("fault")->addChild("value")->addChild("struct");
  
          $member = $struct->addChild("member");
          $member->addChild("name", "faultCode");
          $member->addChild("value")->addChild("int", $code);
  
          $member = $struct->addChild("member");
          $member->addChild("name", "faultString");
          $member->addChild("value", $message);
  
          return $response->asXML();
      }
docs: creates a xml-rpc fault
  
  @param int $code
  @param string $message
  @return string