code: func (a *AttemptList) Normalize() error {
  	for q, vals := range a.GetTo() {
  		if vals == nil {
  			a.To[q] = &AttemptList_Nums{}
  		} else {
  			if err := vals.Normalize(); err != nil {
  				return err
  			}
  		}
  	}
  	return nil
  }
docs: // Normalize sorts and uniq's attempt nums