public function widget($theme = null, $type = null, $callback = null, array $attributes = array())
    {
        $attributes['class'] = implode(' ', array_merge((array)(isset($attributes['class']) ? $attributes['class'] : null), ['g-recaptcha']));
        $attributes['data-sitekey'] = $this->siteKey;
        $attributes['data-theme'] = $theme;
        $attributes['data-type'] = $type;
        $attributes['data-callback'] = $callback;

        return '<div' . HtmlBuilder::attributes($attributes) . '></div>';
    }