code: def device_name() -> str:
      """Returns the singleton DTensor device's name.
  
      This function can be used in the following way:
  
      ```python
      import tensorflow as tf
  
      with tf.device(dtensor.device_name()):
        # ...
      ```
      """
      return _dtensor_device().name
  
imports: import contextlib
  import threading
  from typing import Any, Callable, Optional, Sequence
  from tensorflow.dtensor.python import dtensor_device
  from tensorflow.dtensor.python import gen_dtensor_ops
  from tensorflow.dtensor.python import layout
  from tensorflow.python.eager import context
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor
  from tensorflow.python.util import deprecation
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 5 for calling a global function with example usage: device_name() and returns: _dtensor_device