code: def set_visible_devices(devices, device_type=None):
      """Set the list of visible devices.
  
      Specifies which `PhysicalDevice` objects are visible to the runtime.
      TensorFlow will only allocate memory and place operations on visible
      physical devices, as otherwise no `LogicalDevice` will be created on them.
      By default all discovered devices are marked as visible.
  
      The following example demonstrates disabling the first GPU on the machine.
  
      >>> physical_devices = tf.config.list_physical_devices('GPU')
      >>> try:
      ...   # Disable first GPU
      ...   tf.config.set_visible_devices(physical_devices[1:], 'GPU')
      ...   logical_devices = tf.config.list_logical_devices('GPU')
      ...   # Logical device was not created for first GPU
      ...   assert len(logical_devices) == len(physical_devices) - 1
      ... except:
      ...   # Invalid device or cannot modify virtual devices once initialized.
      ...   pass
  
      Args:
        devices: List of `PhysicalDevice`s to make visible
        device_type: (optional) Only configure devices matching this device type.
          For example "CPU" or "GPU". Other devices will be left unaltered.
  
      Raises:
        ValueError: If argument validation fails.
        RuntimeError: Runtime is already initialized.
      """
      context.context().set_visible_devices(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 20 for calling a global function with example usage: set_visible_devices(devices, device_type) without return types