code: func NewDiscovery(conf *SDConfig, l log.Logger) (*refresh.Discovery, error) {
  	r, err := newRefresher(conf, l)
  	if err != nil {
  		return nil, err
  	}
  	return refresh.NewDiscovery(
  		l,
  		"openstack",
  		time.Duration(conf.RefreshInterval),
  		r.refresh,
  	), nil
  
  }
docs: // NewDiscovery returns a new OpenStack Discoverer which periodically refreshes its targets.