private function importExampleWebsite(): ?RedirectResponse
    {
        $installTool = $this->container->get('contao.install_tool');
        $templates = $installTool->getTemplates();

        $this->context['templates'] = $templates;

        if ($installTool->getConfig('exampleWebsite')) {
            $this->context['import_date'] = date('Y-m-d H:i', $installTool->getConfig('exampleWebsite'));
        }

        $request = $this->container->get('request_stack')->getCurrentRequest();

        if (null === $request) {
            throw new \RuntimeException('The request stack did not contain a request');
        }

        if ('tl_template_import' !== $request->request->get('FORM_SUBMIT')) {
            return null;
        }

        $template = $request->request->get('template');

        if ('' === $template || !\in_array($template, $templates, true)) {
            $this->context['import_error'] = $this->trans('import_empty_source');

            return null;
        }

        try {
            $installTool->importTemplate($template, '1' === $request->request->get('preserve'));
        } catch (DBALException $e) {
            $installTool->persistConfig('exampleWebsite', null);
            $installTool->logException($e);

            $this->context['import_error'] = $this->trans('import_exception');

            return null;
        }

        $installTool->persistConfig('exampleWebsite', time());

        return $this->getRedirectResponse();
    }