code: def on_trial_result(self, iteration, trials, trial, result, **info):
      self.counter += 1
  
file_path: ray/python/ray/tune/tests/test_callbacks.py
imports: import pytest
  from typing import Dict, Optional
  from ray.tune.callback import Callback, CallbackList
label_desc: Use image node_id 2 for calling the StatefulCallback obj's underlying member method code with example usage: obj.on_trial_result(iteration, trials, trial, result) without return types