FluentDOM::getSerializerFactories PHP Method

    public static function getSerializerFactories()
    {
        if (!self::$_serializerFactories instanceof FluentDOM\Serializer\Factory) {
            $xml = function ($contentType, \DOMNode $node) {
                return new FluentDOM\Serializer\Xml($node);
            };
            $html = function ($contentType, \DOMNode $node) {
                return new FluentDOM\Serializer\Html($node);
            };
            $json = function ($contentType, \DOMNode $node) {
                return new FluentDOM\Serializer\Json($node);
            };
            self::$_serializerFactories = new FluentDOM\Serializer\Factory\Group(['text/html' => $html, 'html' => $html, 'text/xml' => $xml, 'xml' => $xml, 'text/json' => $json, 'json' => $json]);
        }
        return self::$_serializerFactories;
    }

 /**
  * @param Serializer\Factory\Group|NULL $factories
  * @return Serializer\Factory\Group
  */
 public function serializerFactories(Serializer\Factory\Group $factories = NULL)
 {
     if (isset($factories)) {
         $this->_serializerFactories = $factories;
     } elseif (NULL === $this->_serializerFactories) {
         $this->_serializerFactories = \FluentDOM::getSerializerFactories();
     }
     return $this->_serializerFactories;
 }