code: def root_rhx_gis(self) -> Optional[str]:
          
          if self.is_logged_in:
              # At the moment, rhx_gis seems to be required for anonymous requests only. By returning None when logged
              # in, we can save the root_rhx_gis lookup query.
              return None
          if not self._root_rhx_gis:
              self._root_rhx_gis = self.get_json('', {})['rhx_gis']
          return self._root_rhx_gis
docs: rhx_gis string returned in the / query.