public function registerStyleSheetFile($key, $url, $media = '')
{
if ($media === '') {
$this->_styleSheetFiles[$key] = $url;
} else {
$this->_styleSheetFiles[$key] = array($url, $media);
}
$params = func_get_args();
$this->_page->registerCachingAction('Page.ClientScript', 'registerStyleSheetFile', $params);
}