code: func (r *GormWorkItemRepository) Fetch(ctx context.Context, spaceID uuid.UUID, criteria criteria.Expression) (*WorkItem, error) {
  	defer goa.MeasureSince([]string{"goa", "db", "workitem", "fetch"}, time.Now())
  
  	limit := 1
  	results, count, err := r.List(ctx, spaceID, criteria, nil, nil, &limit, SortWorkItemsByDefault)
  	if err != nil {
  		return nil, err
  	}
  	// if no result
  	if count == 0 {
  		return nil, nil
  	}
  	// one result
  	result := results[0]
  	return &result, nil
  }
docs: // Fetch fetches the (first) work item matching by the given criteria.Expression.