code: func (d *driver) Leave(nid, eid string) error {
  	defer osl.InitOSContext()()
  	network, err := d.getNetwork(nid)
  	if err != nil {
  		return err
  	}
  	endpoint, err := network.getEndpoint(eid)
  	if err != nil {
  		return err
  	}
  	if endpoint == nil {
  		return fmt.Errorf("could not find endpoint with id %s", eid)
  	}
  
  	return nil
  }
docs: // Leave method is invoked when a Sandbox detaches from an endpoint.