code: def apply_config(self, config):
          
          self.discovery = config["discovery"]
          self.meta_cluster = config.get("meta_cluster")
          for balancer_name in Balancer.get_installed_classes().keys():
              if balancer_name in config:
                  setattr(self, balancer_name, config[balancer_name])
docs: Sets the `discovery` and `meta_cluster` attributes, as well as the
          configured + available balancer attributes from a given validated
          config.