def update_optimizer(self, runner: "IRunner") -> None:
        """Update learning rate and momentum in runner.

        Args:
            runner: current runner
        """
        lr, momentum = self._update_optimizer(optimizer=self.optimizer)

        if self.optimizer_key is not None:
            runner.batch_metrics[f"lr_{self.optimizer_key}"] = lr
            runner.batch_metrics[f"momentum_{self.optimizer_key}"] = momentum
        else:
            runner.batch_metrics["lr"] = lr
            runner.batch_metrics["momentum"] = momentum
Update learning rate and momentum in runner.

        Args:
            runner: current runner
        
catalyst/callbacks/scheduler.py