code: def test_trainer_mps_accelerator(accelerator_value):
      trainer = Trainer(accelerator=accelerator_value)
      assert isinstance(trainer.accelerator, MPSAccelerator)
      assert trainer.num_devices == 1
  
file_path: pytorch-lightning/tests/tests_pytorch/accelerators/test_mps.py
imports: from collections import namedtuple
  import pytest
  import torch
  from lightning.pytorch import Trainer
  from lightning.pytorch.accelerators import MPSAccelerator
  from lightning.pytorch.demos.boring_classes import BoringModel
  import tests_pytorch.helpers.pipelines
  from tests_pytorch.helpers.runif import RunIf
label_desc: Use image node_id 4 for calling a global function with example usage: test_trainer_mps_accelerator(accelerator_value) without return types