RPC - sort_keys documentation inconsistencies und clarifications

[KryptomineCH]

Several Endpoints such as get_all_offers have a property sort_key

What is the default sort_key and how do I know which sort keys are available/refer to which properties?

At the time I'm particularly interested for the endpoints get_all_offers and get_transactions

---

Notably the documentation on get_all_offers shows its of type string. The documentation on get_transactions shows its of type number

---

I tried to test a little and it seems either the sort key is not implemented or it is not trivial. Or the type is not long/int:

{{
  "offers": null,
  "trade_records": null,
  "success": false,
  "error": "No known sort 0"
}}

string is not trivial either:

GetAllOffers_RPC getAllOffers_RPC = new GetAllOffers_RPC(
    start: heightInfo.ImportedOfferHeight.SequenceHeight,
    end: long.MaxValue,
    exclude_my_offers: false,
    exclude_taken_offers: false,
    include_completed: true,
    sort_key: null,//"created_at_time",
    reverse: true,
    file_contents: true) ;

{{
  "offers": null,
  "trade_records": null,
  "success": false,
  "error": "No known sort created_at_time"
}}