public function run(): string
    {
        $params = [
            'fields' => $this->fields,
            'model'  => $this->model,
            'form'   => $this->form,
        ];

        if ($this->languageModel === null) {
            $template = 'fieldsSimple';
        } else {
            $template = 'fieldsMultilanguage';
            $params['languageModel'] = $this->languageModel;
        }

        return $this->render($template, $params);
    }