protected function _normalizeConfig($config)
    {
        if (empty($config['driver'])) {
            if (empty($config['service'])) {
                throw new MissingConnectionException(['name' => $config['name']]);
            }

            if (!$config['driver'] = App::className($config['service'], 'Webservice/Driver')) {
                throw new MissingDriverException(['driver' => $config['driver']]);
            }
        }

        return $config;
    }