code: func (d *Devices) Start() (err error) {
  	log.Println("Starting devices...")
  	for _, device := range *d {
  		info := "Starting device " + device.Name()
  
  		if pinner, ok := device.(Pinner); ok {
  			info = info + " on pin " + pinner.Pin()
  		}
  
  		log.Println(info + "...")
  		if derr := device.Start(); derr != nil {
  			err = multierror.Append(err, derr)
  		}
  	}
  	return err
  }
docs: // Start calls Start on each Device in d