FluentDOM\Constraints::isNodeList PHP Метод

    public static function isNodeList($elements)
    {
        if ($elements instanceof \Traversable || is_array($elements)) {
            return empty($elements) ? new \EmptyIterator() : $elements;
        }
        return NULL;
    }

 /**
  * @param mixed $content
  * @param bool $includeTextNodes
  * @param int $limit
  * @return array|\Traversable null
  */
 private function getNodeList($content, $includeTextNodes = TRUE, $limit = -1)
 {
     if ($callback = Constraints::isCallable($content)) {
         $content = $callback();
     }
     if ($content instanceof \DOMElement) {
         return array($content);
     } elseif ($includeTextNodes && Constraints::isNode($content)) {
         return array($content);
     } elseif (Constraints::isNodeList($content)) {
         return $this->getLimitedArray($content, $limit);
     }
     return NULL;
 }