'Does the work.'

@flow.StateHandler()
def ProcessClients(self, unused_responses):

    self.start = 0
    self.end = int((1000000.0 * (time.time() - self.MAX_AGE)))
    client_urns = export_utils.GetAllClients(token=self.token)
    for batch in utils.Grouper(client_urns, 10000):
        with data_store.DB.GetMutationPool(token=self.token) as mutation_pool:
            for client_urn in batch:
                mutation_pool.DeleteAttributes(client_urn.Add('stats'), [u'aff4:stats'], start=self.start, end=self.end)
        self.HeartBeat()
