protected function getSchemaResponse($schemaID, $form = null, ValidationResult $errors = null, $extraData = [])
    {
        $parts = $this->owner->getRequest()->getHeader(LeftAndMain::SCHEMA_HEADER);
        $data = $this->owner
            ->getFormSchema()
            ->getMultipartSchema($parts, $schemaID, $form, $errors);

        if ($extraData) {
            $data = array_merge($data, $extraData);
        }

        $response = HTTPResponse::create(Convert::raw2json($data));
        $response->addHeader('Content-Type', 'application/json');

        return $response;
    }