/**
  * @param CssAsset $asset
  * @return mixed
  * @throws HelperMethodNotFoundException
  */
 public function renderCss(CssAsset $asset)
 {
     $helper = $this->helpers[$this->assetTypes['css']['helper']];
     if (!is_a($helper, 'Helper') || !method_exists($helper, 'css')) {
         throw new HelperMethodNotFoundException();
     }
     return $helper->css($asset->getPath(), $asset->getRel(), array('inline' => TRUE));
 }