Use new Key() constructor signature in get_or_insert().
Use new Key() constructor signature in get_or_insert().

NOTE: This adds some new keyword args to get_or_insert();
a potential problem with that is that you cannot use those
keywords as property names any more (when using get_or_insert()).

GoogleCloudPlatform/datastore-ndb-python,GoogleCloudPlatform/datastore-ndb-python