code: def _traverse_parent_objs(self, goobj_child):
          
          child_id = goobj_child.id
          # mark child as seen
          self.seen_cids.add(child_id)
          self.godag.go2obj[child_id] = goobj_child
          # Loop through parents of child object
          for parent_obj in goobj_child.parents:
              parent_id = parent_obj.id
              self.godag.p_from_cs[parent_id].add(child_id)
              # If parent has not been seen, traverse
              if parent_id not in self.seen_cids:
                  self._traverse_parent_objs(parent_obj)
docs: Traverse from source GO up parents.