protected function _setBtnClass($button, array $options = [])
    {
        if ($button !== true) {
            $classes = [$this->_configRead('btnPref')];
            foreach ((array) $button as $button) {
                $classes[] = $this->_configRead('btnPref') . '-' . $button;
            }
            $options = $this->_addClass($options, implode(' ', $classes));
        }

        return $options;
    }