code: def test_cascade_delete_on_trial(session: Session) -> None:
      trial = TestTrialValueModel._create_model(session)
      trial.values.append(
          TrialValueModel(
              trial_id=1,
              objective=1,
              value=20,
              value_type=TrialValueModel.TrialValueType.FINITE,
          )
      )
      session.commit()
  
      assert 2 == len(
          TrialValueModel.where_trial_id(trial.trial_id, session)
      )
  
      session.delete(trial)
      session.commit()
  
      assert 0 == len(
          TrialValueModel.where_trial_id(trial.trial_id, session)
      )
  
imports: from datetime import datetime
  import pytest
  from sqlalchemy import create_engine
  from sqlalchemy.exc import IntegrityError
  from sqlalchemy.orm import Session
  from optuna.storages._rdb.models import BaseModel
  from optuna.storages._rdb.models import StudyDirectionModel
  from optuna.storages._rdb.models import StudyModel
  from optuna.storages._rdb.models import StudySystemAttributeModel
  from optuna.storages._rdb.models import TrialHeartbeatModel
  from optuna.storages._rdb.models import TrialIntermediateValueModel
  from optuna.storages._rdb.models import TrialModel
  from optuna.storages._rdb.models import TrialSystemAttributeModel
  from optuna.storages._rdb.models import TrialUserAttributeModel
  from optuna.storages._rdb.models import TrialValueModel
  from optuna.storages._rdb.models import VersionInfoModel
  from optuna.study._study_direction import StudyDirection
  from optuna.trial import TrialState
label_desc: Use image node_id 4 for calling the TestTrialValueModel obj's underlying member method code with example usage: obj.test_cascade_delete_on_trial(session) without return types