code: def test_dont_prune(self):
      trial = Mock()
      trial.should_prune.return_value = False
      optuna_pruner_hook = pfrl.experiments.OptunaPrunerHook(
          trial=trial
      )
  
      env = Mock()
      agent = Mock()
      evaluator = Mock()
      step = 42
      eval_stats = {"mean": 3.14}
      agent_stats = [("dummy", 2.7)]
      env_stats = []
  
      optuna_pruner_hook(
          env,
          agent,
          evaluator,
          step,
          eval_stats,
          agent_stats,
          env_stats,
      )
  
      trial.report.assert_called_once_with(eval_stats["mean"], step)
  
imports: import unittest
  from unittest.mock import Mock
  import optuna
  import pfrl
label_desc: Use image node_id 1 for calling the TestOptunaPrunerHook obj's underlying member method code with example usage: obj.test_dont_prune() without return types