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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def update_keys(self):
 """ Update the redis keys to listen for new jobs priorities. """

        self.keys = self.queue_model.get_waiting_keys(self.queues)

        if not self.keys:
            self.log('No queues yet', level='warning')
        self.last_update_keys = datetime.utcnow()