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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_model(self, updates=None):
 """ Get or set, whether automatic updates are performed. When updates are off, the model might be in a non-working state. To make the model work turn updates on again. :param bool|None updates: bool: whether to do updates None: get the current update state """

        if updates is None:
            return self._update_on
        assert isinstance(updates, bool), "updates are either on (True) or off (False)"
        p = getattr(self, '_highest_parent_', None)
        def turn_updates(s):
            s._update_on = updates
        p.traverse(turn_updates)
        self.trigger_update()