code: def train(self):
      time.sleep(0.2)
      print("train ", self.i)
  
file_path: ray/release/nightly_tests/placement_group_tests/pg_run.py
imports: import os
  import time
  import json
  import ray
  from ray.util.placement_group import placement_group
  from ray.util.scheduling_strategies import PlacementGroupSchedulingStrategy
label_desc: Use image node_id 2 for calling the Trainer obj's underlying member method code with example usage: obj.train() without return types