class_docstr: Tests for mesh_util that require accelerator initialization.
class_docstr_tok: ["Tests","for","mesh_util","that","require","accelerator","initialization","."]
code: def test_initialize_error_vgpu_with_nccl(self):
      self.skipForDeviceType(
          ["CPU", "TPU"], reason="Test is intended for GPUs"
      )
  
      accelerator_util.shutdown_accelerator_system()
      num_physical_devices = config.num_local_devices("GPU")
      test_util.reset_logical_devices("GPU", 2 * num_physical_devices)
      with self.assertRaisesRegex(
          ValueError, "DTENSOR_GPU_USE_NCCL_COMMUNICATION"
      ):
          accelerator_util.initialize_accelerator_system("GPU")
  
imports: import os
  from unittest import mock
  from absl.testing import parameterized
  from tensorflow.dtensor.python import accelerator_util
  from tensorflow.dtensor.python import config
  from tensorflow.dtensor.python import mesh_util
  from tensorflow.dtensor.python.tests import test_util
  from tensorflow.python.eager import context
  from tensorflow.python.framework import config
  from tensorflow.python.framework import device
  from tensorflow.python.platform import test
label_desc: Use image node_id 5 for calling the InitializedMeshUtilTest obj's underlying member method code with example usage: obj.test_initialize_error_vgpu_with_nccl() without return types