Python 3.9 is now generally available.

google.appengine.api.datastore.NormalizeAndTypeCheckKeys

Normalizes and type checks that the given argument is a valid key or keys.

A wrapper around NormalizeAndTypeCheck() that accepts strings, Keys, and Entities, and normalizes to Keys.

keys a Key or sequence of Keys

A (list of Keys, bool) tuple. See NormalizeAndTypeCheck.

BadArgumentError arg is not an instance or sequence of one of the given types.