code: def _add_discovery_config(self):
      
      lookup_key = (discovery_service.DiscoveryService.API_CONFIG['name'],
                    discovery_service.DiscoveryService.API_CONFIG['version'])
      self._configs[lookup_key] = discovery_service.DiscoveryService.API_CONFIG
docs: Add the Discovery configuration to our list of configs.
  
      This should only be called with self._config_lock.  The code here assumes
      the lock is held.