Suggested approach: Start out with a simple definition of what
NSSortDescriptor actually does: it lets us provide sorting instructions to a data store, e.g. "sort by name alphabetically".
Once you've done that you should go on to mention that it's most commonly when used in Core Data to sort the data that got fetched, but it's also available in CloudKit.
For bonus points, talk about how it can be a stringly typed API, or you can use key paths instead.
Estimated difficulty: Intermediate
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