code: def test_unpatch_cuda(self):
      from bigdl.nano.pytorch import patch_torch, unpatch_torch
  
      patch_torch(cuda_to_cpu=True)
      patch_torch(cuda_to_cpu=True)  # call patch twice
      import torch
  
      unpatch_torch()
  
      with pytest.raises(
          (RuntimeError, AssertionError), match="CUDA|NVIDIA"
      ):
          _t = torch.tensor([0], device="cuda:0")
          invalidOperationError(False, "cuda unpatch is incorrect")
  
      cuda_device = torch.device("cuda:0")
      assert cuda_device.type == "cuda"
  
file_path: BigDL/python/nano/test/pytorch/tests/test_dispatcher.py
imports: from unittest import TestCase
  import tempfile
  import os
  import pytest
  import torch
  from bigdl.nano.utils.common import invalidOperationError
  from bigdl.nano.utils.pytorch import TORCH_VERSION_LESS_1_10
label_desc: Use image node_id 3 for calling the TestDispatcherPytorch obj's underlying member method code with example usage: obj.test_unpatch_cuda() without return types