public function getRoles($verbose = false) {
        if (Zend_Registry::isRegistered('Zend_Acl')) {
            $acl = Zend_Registry::get('Zend_Acl');
            $roles = $acl->getRoles();

            // collect parents
            if ($verbose) {
                $roles = array_fill_keys($roles, array());
                foreach (array_keys($roles) as $role) {
                    $roles[$role]['parents'] = $this->getRoleParents($role);
                    $roles[$role]['children'] = $this->getRoleChildren($role);
                }
            }
            return $roles;
        }
        return array();
    }