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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 is_descendant_of(self, other, include_self=False):
 """Is this node a descendant of `other`?"""

        if other.pk == self.pk:
            return include_self

        return self._closure_model.objects.filter(
            parent=other,
            child=self
        ).exclude(pk=self.pk).exists()