code: def step(self, closure: Any) -> None:
      pass
  
file_path: torchrec/torchrec/optim/tests/test_warmup.py
imports: import unittest
  from collections import defaultdict
  from typing import Any
  import torch
  from torch.autograd import Variable
  from torchrec.optim.keyed import KeyedOptimizer
  from torchrec.optim.warmup import WarmupOptimizer, WarmupPolicy, WarmupStage
label_desc: Use image node_id 2 for calling the DummyKeyedOptimizer obj's underlying member method code with example usage: obj.step(closure) without return types