code: func unlockIfHeld(lck *lock.Lock) error {
  	err := lck.Unlock()
  	if err == lock.ErrNotExist {
  		return nil
  	} else if err == nil {
  		dlog.Info("Unlocked existing lock for this machine")
  		return nil
  	}
  
  	return err
  }
docs: // unlockIfHeld will unlock a lock, if it is held by this machine, or return an error.