code: def list_devices(device_type=None):
      """Return all the available devices based on the device type.
  
      Note that this should return the global devices in a distributed setting.
  
      Args:
          device_type: string of `"cpu"`, `"gpu"` or `"tpu"`. Defaults to `"gpu"`
              or `"tpu"` if available when device_type is not provided. Otherwise
              will return the `"cpu"` devices.
  
      Return:
          List of devices that are available for distribute computation.
      """
      device_type = device_type.lower() if device_type else None
      jax_devices = jax.devices(backend=device_type)
      return [
          f"{device.platform}:{device.id}" for device in jax_devices
      ]
  
file_path: keras/keras/backend/jax/distribution_lib.py
imports: import jax
  import numpy
  from keras.utils import jax_utils
label_desc: Use image node_id 1 for calling a global function with example usage: list_devices(device_type) and returns: unknown