code: func resolveNumberByWorkItemID(ctx context.Context, db application.DB, workItemID uuid.UUID) (string, error) {
  	var numberInt int
  	err := application.Transactional(db, func(appl application.Application) error {
  		thisWorkItem, err := appl.WorkItems().LoadByID(ctx, workItemID)
  		if err != nil {
  			log.Error(ctx, map[string]interface{}{
  				"err":        err,
  				"workItemID": workItemID,
  			}, "error retrieving number for workItemID")
  			return errs.Wrapf(err, "error retrieving number for workItemID: %s", workItemID.String())
  		}
  		number := thisWorkItem.Fields[workitem.SystemNumber]
  		var ok bool
  		numberInt, ok = number.(int)
  		if !ok {
  			return errs.Errorf("error converting number for workItemID: %s", workItemID.String())
  		}
  		return nil
  	})
  	return strconv.Itoa(numberInt), err
  }
docs: // resolveNumberByWorkItemID retrieves the work item number for a work item ID