code: def setUpClass(cls):
      # Pick one device from each available platform
      cls.devices = []
      cls.platforms = []
      for backend in ["cpu", "gpu", "tpu"]:
          try:
              devices = jax.devices(backend)
          except RuntimeError:
              devices = []
  
          for d in devices:
              if d.platform not in cls.platforms:
                  cls.platforms.append(d.platform)
                  cls.devices.append(d)
      super().setUpClass()
  
file_path: jax/tests/export_harnesses_multi_platform_test.py
imports: from __future__ import annotations
  import math
  import re
  from typing import Callable
  from absl import logging
  from absl.testing import absltest
  import numpy
  import jax
  from jax import lax
  from jax._src import test_util
  from jax.experimental import export
  from jax._src.internal_test_util import test_harnesses
label_desc: Use image node_id 1 for calling the PrimitiveTest obj's underlying member method code with example usage: obj.setUpClass(cls) without return types