public function hasPage(Page $page, $recursive = false)
        {
            if (array_key_exists($page->hashCode(), $this->_index)) {
                return true;
            } elseif ($recursive) {
                foreach ($this->_pages as $childPage) {
                    if ($childPage->hasPage($page, true)) {
                        return true;
                    }
                }
            }

            return false;
        }