code: def testRegisterCustomDevice(self):
      device_name = "/job:localhost/replica:0/task:0/device:CUSTOM:0"
      (
          device,
          device_info,
          arrived_flag,
          executed_flag,
      ) = custom_device_testutil.GetLoggingDeviceCapsules(device_name)
      context.register_custom_device(device, device_name, device_info)
      self.assertFalse(custom_device_testutil.FlagValue(arrived_flag))
      self.assertFalse(custom_device_testutil.FlagValue(executed_flag))
      with ops.device(device_name):
          x = constant_op.constant(1.0)
          y = x * constant_op.constant(2.0)
      self.assertTrue(custom_device_testutil.FlagValue(executed_flag))
      # There was no copy onto the device. Actually I'm not sure how to trigger
      # that from Python.
      self.assertFalse(custom_device_testutil.FlagValue(arrived_flag))
      with self.assertRaisesRegex(
          errors.InternalError, "Trying to copy"
      ):
          y.numpy()
  
file_path: tensorflow/tensorflow/python/eager/custom_device_test.py
imports: from tensorflow.python.eager import context
  from tensorflow.python.eager import custom_device_testutil
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 2 for calling the CustomDeviceTest obj's underlying member method code with example usage: obj.testRegisterCustomDevice() without return types