code: def _update_api_client(self, api_parent_class=None):
          
          clients = ([self.api_clients[api_parent_class]]
                     if api_parent_class else self.api_clients.values())
  
          for api_client in clients:
              api_client.configuration.host = (self.config.get('host') or
                                               api_client.configuration.host)
              api_client.configuration.api_key['Authorization'] = self.config['api_key']
docs: Updates the ApiClient object of specified parent api (or all of them)