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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 get_queryset(self, *args, **kwargs):
 """ Ensures that this manager always returns nodes in tree order. """

        qs = super(TreeManager, self).get_queryset(*args, **kwargs)

        # Restrict operations to pages on the current site if needed
        if settings.PAGES_HIDE_SITES and settings.PAGES_USE_SITE_ID:
            return qs.order_by(self.tree_id_attr, self.left_attr).filter(sites=settings.SITE_ID)
        else:
            return qs.order_by(self.tree_id_attr, self.left_attr)