code: def update_config(self, cluster_config):
          
          for key, attr in [
                  ('ssh_to', 'ssh_to'),
          ]:
              oldvalue = getattr(self, attr)
              try:
                  newvalue = cluster_config[key]
              except KeyError:
                  continue
              if key in cluster_config and newvalue != oldvalue:
                  setattr(self, attr, newvalue)
                  log.debug(
                      "Configuration attribute `%s` updated: %s -> %s",
                      key, oldvalue, newvalue)
docs: Update current configuration.
  
          This method is usually called after loading a `Cluster`
          instance from a persistent storage. Note that not all fields
          are actually updated, but only those that can be safely
          updated.