private function _checkModelProperty()
    {
        if (!$this->model) {
            if (Lang::has('resource-composer.propertynotset')) {
                $message = trans('resource-composer.propertynotset', ['property' => '$model']);
            } else {
                $message = '$model property must be set.';
            }

            throw new ResourceComposerException($message);
        }
    }