function get_container($container_name=NULL)
    {
        list($status, $reason, $count, $bytes) =
                $this->cfs_http->head_container($container_name);
        #if ($status == 401 && $this->_re_auth()) {
        #    return $this->get_container($container_name);
        #}
        if ($status == 404) {
            throw new NoSuchContainerException("Container not found.");
        }
        if ($status < 200 || $status > 299) {
            throw new InvalidResponseException(
                "Invalid response: ".$this->cfs_http->get_error());
        }
        return new CF_Container($this->cfs_auth, $this->cfs_http,
            $container_name, $count, $bytes);
    }