def METHOD_NAME(self):
    """Performs a single learning rate schedule step.
    """
    self.last_step += 1
    if self.last_step > 0:
        lrs = [
            group["lr"] * lmbda(self.last_step)
            for lmbda, group in zip(self.lr_lambdas, self.optimizer.param_groups)
        ]
    else:
        lrs = [group["lr"] for group in self.optimizer.param_groups]
    self.update_lrs(lrs)