public function addServers(array $servers = array())
    {
        $result = true;

        foreach ($servers as $server) {
            if (false === is_array($server)) {
                throw new CacheException('Memcache adapter: server configuration is not an array.');
            }

            $server = array_merge($this->_default_server, $server);
            $result = $result && $this->addServer($server['host'], $server['port'], true, $server['weight']);

            $this->setServerList($server);
        }

        return $result;
    }