code: def _init(self):
          
          for goid in self.godag.go_sources:
              goobj = self.godag.go2obj[goid]
              self.godag.go2obj[goid] = goobj
              # Traverse up parents
              if self.traverse_parent and goid not in self.seen_cids:
                  self._traverse_parent_objs(goobj)
              # Traverse down children
              if self.traverse_child and goid not in self.seen_pids:
                  self._traverse_child_objs(goobj)
docs: Given GO ids and GOTerm objects, create mini GO dag.