code: def get_all_parent_edges(self):
          
          all_parent_edges = set()
          for parent in self.parents:
              all_parent_edges.add((self.item_id, parent.item_id))
              all_parent_edges |= parent.get_all_parent_edges()
          return all_parent_edges
docs: Return tuples for all parent GO IDs, containing current GO ID and parent GO ID.