code: def test_cached_phony():
      p1 = get_phony(torch.device("cpu"), requires_grad=True)
      p2 = get_phony(torch.device("cpu"), requires_grad=True)
      assert p1 is p2
  
      p3 = get_phony(torch.device("cpu"), requires_grad=False)
      p4 = get_phony(torch.device("cpu"), requires_grad=False)
      assert p3 is p4
  
      assert p1 is not p3
  
imports: import torch
  from torch.distributed.pipeline.sync.phony import get_phony
  from torch.testing._internal.common_utils import run_tests
label_desc: Use image node_id 3 for calling a global function with example usage: test_cached_phony() without return types