protected function validateTemplate($template_file)
    {
        $is_valid = false;

        if (!$template_file instanceof \SplFileInfo) {
            $template_file = new \SplFileInfo($template_file);
        }

        // Is this a routable template?
        if (
            $template_file->isFile() &&
            $template_file->isReadable() &&
            ('html' === $template_file->getExtension())
        ) {
            $is_valid = true;
        }

        return($is_valid);
    }