code: def test_passing_env_variables_devices(cuda_count_2):
      """Testing overwriting trainer arguments."""
      trainer = Trainer()
      assert trainer.num_devices == 2
      trainer = Trainer(accelerator="gpu", devices=1)
      assert trainer.num_devices == 1
  
file_path: pytorch-lightning/tests/tests_pytorch/trainer/flags/test_env_vars.py
imports: import os
  from unittest import mock
  from lightning.pytorch import Trainer
  from lightning.pytorch.demos.boring_classes import BoringModel
label_desc: Use image node_id 4 for calling a global function with example usage: test_passing_env_variables_devices(cuda_count_2) without return types