code: def test_lambda_scheduler(self):
      def scheduler_function(epoch):
          return 1 - epoch / 10
  
      scheduler = LambdaGradClip(
          self.optimizer, scheduler_function=scheduler_function
      )
  
      self.assertEqual(self.optimizer.max_grad_norm, 1.0)
      scheduler.step()
      self.assertEqual(
          self.optimizer.max_grad_norm, scheduler_function(1)
      )
  
file_path: opacus/opacus/tests/schedulers/grad_clip_scheduler_test.py
imports: import unittest
  import torch
  from opacus import PrivacyEngine
  from opacus.schedulers import ExponentialGradClip, LambdaGradClip, StepGradClip
  from torch import nn, optim
  from torch.utils.data import DataLoader, TensorDataset
label_desc: Use image node_id 4 for calling the GradClipSchedulerTest obj's underlying member method code with example usage: obj.test_lambda_scheduler() and returns: unknown