Incorrect results of allocate_ids when running on local dev_appserver.py

[ivan starkov]

this code:

class AnyYourDBModelClass(db.Model):

         some_uid = db.IntProperty() #=key

handmade_key = db.Key.from_path('AnyYourDBModelClass', 1)

numid_start, numid_end = db.allocate_ids(handmade_key, 1);

allocate_ids must return unique values forever

but this is not true for local dev_appserver.py, 

values repeated after each restart of  dev_appserver.py (db is not cleaned)