code: func (r *GormWorkItemRepository) LoadBottomWorkitem(ctx context.Context, spaceID uuid.UUID) (*WorkItem, error) {
  	res := WorkItemStorage{}
  	db := r.db.Model(WorkItemStorage{})
  	query := fmt.Sprintf("execution_order = (SELECT min(execution_order) FROM %[1]s where space_id=?)",
  		WorkItemStorage{}.TableName(),
  	)
  	db = db.Where(query, spaceID).First(&res)
  	if db.Error != nil && !db.RecordNotFound() {
  		return nil, errors.NewInternalError(ctx, db.Error)
  	}
  	wiType, err := r.witr.Load(ctx, res.Type)
  	if err != nil {
  		return nil, errors.NewInternalError(ctx, err)
  	}
  	return ConvertWorkItemStorageToModel(wiType, &res)
  }
docs: // LoadBottomWorkitem returns bottom work item of the list. Bottom most workitem has the lowest order.
  // returns NotFoundError, ConversionError or InternalError