code: def test_tpu_device_absence():
      """Check `is_available` returns True when TPU is available."""
      assert not XLAAccelerator.is_available()
  
imports: import pytest
  from lightning.fabric.accelerators.xla import _XLA_AVAILABLE, XLAAccelerator
  from tests_fabric.helpers.runif import RunIf
label_desc: Use image node_id 2 for calling a global function with example usage: test_tpu_device_absence() without return types