code: def test_invoke_in_pt2(self):
      for backend in ["eager", "aot_eager", "inductor"]:
          torch._dynamo.reset()
          x = torch.tensor([0.5, 0.5], requires_grad=True)
          y = torch.tensor([0.5, 0.5], requires_grad=True)
  
          def fn(x, y):
              x.register_hook(_multiply_invoke)
              return x * y
  
          fn = torch._dynamo.optimize(backend)(fn)
          out = fn(x, y)
          grad_out = torch.tensor([2.0, 2.0])
          out.backward(grad_out)
          self.assertEqual(x.grad, grad_out * y)
  
imports: import functools
  import torch
  import torch._dynamo.test_case
  import torch._dynamo.testing
  import torch._dynamo.utils
  from torch import _inductor
  from torch._dynamo import compiled_autograd
  from torch._dynamo._trace_wrapped_higher_order_op import trace_wrapped
  from torch._dynamo.testing import normalize_gm
  from torch._dynamo.utils import counters
  from torch.fx.experimental.proxy_tensor import make_fx
label_desc: Use image node_id 2 for calling the BackwardHigherOrderOpTests obj's underlying member method code with example usage: obj.test_invoke_in_pt2() and returns: unknown