public static function group($buttons, $htmlOptions = array())
    {
        ArrayHelper::addValue('class', 'button-group', $htmlOptions);

        ob_start();
        echo \CHtml::openTag('ul', $htmlOptions);
        foreach ($buttons as $button) {
            echo $button;
        }
        echo \CHtml::closeTag('ul');

        return ob_get_clean();
    }