code: def test_gather_gpu(self):
      self._test_gather(0)
  
imports: import contextlib
  import io
  from copy import deepcopy
  from collections import OrderedDict
  from itertools import product
  import functools
  import torch
  from torch import nn
  from torch.cuda.amp import autocast
  import torch.nn.parallel
  from torch.testing._internal.common_cuda import TEST_MULTIGPU, TEST_CUDA
  from torch.testing._internal.common_device_type import instantiate_device_type_tests, dtypes, onlyCUDA, skipMeta
  from torch.testing._internal.common_utils import run_tests, TestCase
  from torch.testing._internal.common_utils import _assertGradAndGradgradChecks, gradcheck
  from torch.testing._internal.common_utils import dtype2prec_DONTUSE
  from torch.testing._internal.common_utils import skip_but_pass_in_sandcastle_if
  import torch.nn.functional
label_desc: Use image node_id 25 for calling the TestDataParallel obj's underlying member method code with example usage: obj.test_gather_gpu() without return types