protected static function getMapCallback($revisioned)
    {
        // We need to pass the calling class to the closure scope
        // instead of calling new static(), since php is going
        // to instantiate it w/o late static binding (bug).
        $presenter = get_called_class();

        return function ($revision) use ($presenter, $revisioned) {
            return new $presenter($revision, $revisioned);
        };
    }