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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):
 """Sets the custom queryset as the default."""

        if self.model.node_order_by:
            order_by = ['parent'] + list(self.model.node_order_by)
        else:
            order_by = ['parent', 'sib_order']
        return super(AL_NodeManager, self).get_queryset().order_by(*order_by)