protected function _getSeqIds(Horde_Imap_Client_Ids $ids)
    {
        if (!count($ids)) {
            $status = $this->status($this->_selected, Horde_Imap_Client::STATUS_MESSAGES);
            return range(1, $status['messages']);
        } elseif ($ids->sequence) {
            return $ids->ids;
        }

        return array_keys(array_intersect($this->_pop3Cache('uidl'), $ids->ids));
    }