code: def setUp(self) -> None:
      os.environ["TUNE_PLACEMENT_GROUP_RECON_INTERVAL"] = "0"
      ray.init(num_cpus=6)
  
file_path: ray/python/ray/rllib/tests/test_placement_groups.py
imports: import os
  import unittest
  import ray
  from ray import air
  from ray import tune
  from ray.tune import Callback
  from ray.rllib.algorithms.ppo import PPO, PPOConfig
  from ray.tune.experiment import Trial
  from ray.tune.execution.placement_groups import PlacementGroupFactory
label_desc: Use image node_id 1 for calling the TestPlacementGroups obj's underlying member method code with example usage: obj.setUp() without return types