code: def test_resources(ray_start_4_cpus):
      def check_cpus(self):
          assert ray.available_resources()["CPU"] == 2
  
      assert ray.available_resources()["CPU"] == 4
      trainer = DummyTrainer(
          check_cpus,
          scaling_config=ScalingConfig(trainer_resources={"CPU": 2}),
      )
      trainer.fit()
  
imports: import logging
  import tempfile
  import pytest
  import ray
  from ray import train, tune
  from ray.air.constants import MAX_REPR_LENGTH
  from ray.data.context import DataContext
  from ray.train import Checkpoint, ScalingConfig
  from ray.train.gbdt_trainer import GBDTTrainer
  from ray.train.trainer import BaseTrainer
  from ray.util.placement_group import get_current_placement_group
label_desc: Use image node_id 3 for calling a global function with example usage: test_resources(ray_start_4_cpus) without return types