docs: def rebuildtable(cls):
          """Regenerate the entire closuretree."""
          cls._closure_model.objects.all().delete()
          cls._closure_model.objects.bulk_create([cls._closure_model(
              parent_id=x['pk'],
              child_id=x['pk'],
              depth=0
          ) for x in cls.objects.values("pk")])
          for node in cls.objects.all():
              node._closure_createlink()