code: func (e *Engine) attemptScheduleUnit(name, machID string) bool {
  	err := e.registry.ScheduleUnit(name, machID)
  	if err != nil {
  		log.Errorf("Failed scheduling Unit(%s) to Machine(%s): %v", name, machID, err)
  		return false
  	}
  
  	log.Infof("Scheduled Unit(%s) to Machine(%s)", name, machID)
  	return true
  }
docs: // attemptScheduleUnit tries to persist a scheduling decision in the
  // Registry, returning true on success. If any communication with the
  // Registry fails, false is returned.