code: def get_visible_devices(device_type=None):
      """Get the list of visible physical devices.
  
      Returns the list of `PhysicalDevice`s currently marked as visible to the
      runtime. A visible device will have at least one `LogicalDevice` associated
      with it once the runtime is initialized.
  
      The following example verifies all visible GPUs have been disabled:
  
      >>> physical_devices = tf.config.list_physical_devices('GPU')
      >>> try:
      ...   # Disable all GPUS
      ...   tf.config.set_visible_devices([], 'GPU')
      ...   visible_devices = tf.config.get_visible_devices()
      ...   for device in visible_devices:
      ...     assert device.device_type != 'GPU'
      ... except:
      ...   # Invalid device or cannot modify virtual devices once initialized.
      ...   pass
  
      Args:
        device_type: (optional string) Only include devices matching this device
          type. For example "CPU" or "GPU".
  
      Returns:
        List of visible `PhysicalDevice`s
      """
      return context.context().get_visible_devices(device_type)
  
imports: from typing import Union
  from tensorflow.python.eager import context
  from tensorflow.python.framework import errors
  from tensorflow.python.util import _pywrap_determinism
  from tensorflow.python.util import _pywrap_tensor_float_32_execution
  from tensorflow.python.util import deprecation
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 19 for calling a global function with example usage: get_visible_devices(device_type) and returns: context