public static function getSerializerFactories(): FluentDOM\Serializer\Factory\Group {
    if (NULL === self::$_serializerFactories) {
      $xml = function($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;
  }
public static function getSerializerFactories(): FluentDOM\Serializer\Factory\Group {
    if (NULL === self::$_serializerFactories) {
      $xml = function($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;
  }
public static function getSerializerFactories ( ) : FluentDOM \ Serializer \ Factory \ Group { if ( NULL === self :: $ _serializerFactories ) { $ 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 ; }
Return registered serializer factories

@return FluentDOM\Serializer\Factory\Group
Return registered serializer factories