code: def test_lambda_scheduler(self):
      model = nn.Sequential(nn.Linear(16, 16))
      sparsifier = WeightNormSparsifier()
      sparsifier.prepare(model, config=None)
      assert sparsifier.groups[0]["sparsity_level"] == 0.5
      scheduler = LambdaSL(sparsifier, lambda epoch: epoch * 10)
      assert sparsifier.groups[0]["sparsity_level"] == 0.0  # Epoch 0
      scheduler.step()
      assert sparsifier.groups[0]["sparsity_level"] == 5.0
  
imports: from torch import nn
  from torch.ao.pruning import WeightNormSparsifier
  from torch.ao.pruning import BaseScheduler, LambdaSL, CubicSL
  from torch.testing._internal.common_utils import TestCase
  import warnings
label_desc: Use image node_id 4 for calling the TestScheduler obj's underlying member method code with example usage: obj.test_lambda_scheduler() without return types