Python 3.9 is now generally available.

google.appengine.datastore.datastore_index.GetRecommendedIndexProperties

Converts the properties returned by datastore_index.CompositeIndexForQuery into a recommended list of index properties with the desired constraints.

Sets (of property names or PropertySpec objects) are sorted, so as to normalize them.

properties See datastore_index.CompositeIndexForQuery.

A tuple of PropertySpec objects.