public function sitesManagedByMember($member = null)
    {
        $member = $member ?: Member::currentUser();
        if (!$member) return array();

        $sites = Site::get();

        if (Permission::check('ADMIN')) {
            return $sites->column('ID');
        }

        $memberGroups = $member->Groups()->column('ID');
        $sites        = $sites->filter("EditorGroups.ID:ExactMatch", $memberGroups);

        return $sites->column('ID');
    }