The method objects has an unpleasant randomness

Despite having explicitly an order_by instruction here https://gitlab.idiap.ch/bob/bob.db.mobio/blob/master/bob/db/mobio/query.py#L439 , its output is completely random.

The code below does create two instances of the mobio database, does the same search, but the output is different.

import bob.db.mobio

db_mobio = bob.db.mobio.Database()
train_objects = db_mobio.objects(protocol="male", groups="dev")
print train_objects[0]

db_mobio = bob.db.mobio.Database()
train_objects = db_mobio.objects(protocol="male", groups="dev")
print train_objects[0]