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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_all_lower(self):
 """Return all parent GO IDs through both reverse 'is_a' and all relationships."""

        all_lower = set()
        for lower in self.get_goterms_lower():
            all_lower.add(lower.item_id)
            all_lower |= lower.get_all_lower()
        return all_lower