rhysrevans3

Couple of notes from my pull request: 1. If typing `List` and `Dict` are being used [this part](https://github.com/stac-utils/stac-fastapi/pull/625/files#diff-f84457de825c3fa96fa65673a6f85442ac57bd10f9f939cb7411780d3b6fabb5R46-R47) will need to be changed as in it's current form it will...

@thomas-maschler I found it was an issue for nested List/Dicts types: for example the `sortby` field in the SortExtensionPostRequest is ``` sortby: Optional[List[PostSortModel]] ``` But when I check the `FieldInfo`...

@thomas-maschler ah that makes more sense thank you for the explanation. I guess this just need to be filled in the backend I'm using. Point 2 that sounds like a...

@thomas-maschler sorry about that I've been getting `TypeError: Object of type LandingPage is not JSON serializable` on the landing page when trying to update the [stac-fastapi-elasticsearch-opensearch](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch) to use this branch...

@m-mohr Could I get your opinion on this I know you've helped with the extension definition.

> where are we with this PR? @rhysrevans3 We're unsure on if basic and advanced search are compatible https://github.com/stac-api-extensions/freetext-search/issues/10 I think the current options are, update the advanced search to...