/**
  * Get the priority param of $node from $site
  * 
  * @param ReadNodeInterface $node
  * @param ReadSiteInterface $site
  * 
  * @return float
  */
 protected function getPriority(ReadNodeInterface $node, ReadSiteInterface $site)
 {
     $sitemapPriority = $node->getSitemapPriority();
     if (is_null($sitemapPriority)) {
         $sitemapPriority = $site->getSitemapPriority();
     }
     return $sitemapPriority;
 }