public function getChildren(MenuItem $parent = null)
    {
        if ($parent === null) {
            return $this->getTopChildren();
        }
        /* @var $request Request */
        $request = $this->container->get('request_stack')->getCurrentRequest();
        $result = array();
        foreach ($this->getAdaptors() as $menuAdaptor) {
            $menuAdaptor->adaptChildren($this, $result, $parent, $request);
        }

        return $result;
    }