'Update the timestamp of a trackable
@param track_id: the trackable ID (super-entity key)
@param timestamp: the timestamp'

def __update_timestamp(self, track_id, timestamp):

    if (timestamp is None):
        timestamp = datetime.utcnow()
    if track_id:
        trackable = self.table[track_id]
        if trackable:
            trackable.update_record(track_timestmp=timestamp)
