code: def test_phony_in_autograd_function():
      class Phonify(torch.autograd.Function):
          @staticmethod
          def forward(ctx, input):
              phony = get_phony(input.device, requires_grad=False)
              return phony.detach()
  
      x = torch.rand(1, requires_grad=True)
  
      p1 = Phonify.apply(x)
      p2 = get_phony(torch.device("cpu"), requires_grad=True)
  
      assert p1 is not p2
      assert p1.grad_fn is not None
      assert p2.grad_fn is None
  
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 4 for calling a global function with example usage: test_phony_in_autograd_function() and returns: phony