BadArgumentError: _MultiQuery with cursors requires __key__ order in ndb

Question

I can\'t understand what this error means and apparently, no one ever got the same error on the internet

BadArgumentError: _MultiQuery with cursors re

Answer 1

The error message tries to tell you you that queries involving IN and cursors must be ordered by __key__ (which is the internal name for the key of the entity). (This is needed so that the results can be properly merged and made unique.) In this case you have to replace your .order() call with .order(SocialNotification._key).