def update_iteration(self):
        """Update the last experiment group's iteration with experiment performance."""
        iteration_config = self.get_iteration_config()
        if not iteration_config:
            return
        experiments_metrics = self.experiment_group.get_experiments_metrics(
            experiment_ids=iteration_config.experiment_ids,
            metric=self.get_metric_name()
        )
        iteration_config.experiments_metrics = [m for m in experiments_metrics if m[1] is not None]
        self._update_config(iteration_config)
Update the last experiment group's iteration with experiment performance.