code: def test_gpu(self):
      self._test(torch.device("cuda:0"))
  
file_path: pfrl/tests/utils_tests/test_conjugate_gradient.py
imports: import pytest
  import torch
  import pfrl
  from pfrl.testing import torch_assert_allclose
label_desc: Use image node_id 4 for calling the TestConjugateGradient obj's underlying member method code with example usage: obj.test_gpu() without return types