Inheritance: extends Facebook\InstantArticles\Transformer\Getters\AbstractGetter
 public function get($node)
 {
     $element = parent::get($node);
     if ($element) {
         $fragment = $element->ownerDocument->createDocumentFragment();
         foreach ($element->childNodes as $child) {
             Transformer::markAsProcessed($child);
             $fragment->appendChild(Transformer::cloneNode($child));
         }
         if ($fragment->hasChildNodes()) {
             return $fragment;
         }
     }
     return null;
 }