code: func (o *SortOption) By(index int, ascending bool) *SortOption {
  	order := instruction.Descending
  	if ascending {
  		order = instruction.Ascending
  	}
  	o.orderByList = append(o.orderByList, instruction.OrderBy{
  		Index: index,
  		Order: order,
  	})
  	return o
  }
docs: // OrderBy chains a list of sorting order by