code: func New(ds datastore.DataStore, id string, start, end uint64) (*Idm, error) {
  	if id == "" {
  		return nil, errors.New("Invalid id")
  	}
  	if end <= start {
  		return nil, fmt.Errorf("Invalid set range: [%d, %d]", start, end)
  	}
  
  	h, err := bitseq.NewHandle("idm", ds, id, 1+end-start)
  	if err != nil {
  		return nil, fmt.Errorf("failed to initialize bit sequence handler: %s", err.Error())
  	}
  
  	return &Idm{start: start, end: end, handle: h}, nil
  }
docs: // New returns an instance of id manager for a [start,end] set of numerical ids