code: def _create_model(session: Session) -> StudyModel:
      study = StudyModel(study_id=1, study_name="test-study")
      dummy_study = StudyModel(study_id=2, study_name="dummy-study")
      session.add(
          StudyDirectionModel(
              study_id=study.study_id,
              direction=StudyDirection.MINIMIZE,
              objective=0,
          )
      )
      session.add(
          StudyDirectionModel(
              study_id=dummy_study.study_id,
              direction=StudyDirection.MINIMIZE,
              objective=0,
          )
      )
      session.commit()
      return study
  
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 1 for calling the TestStudyDirectionModel obj's underlying member method code with example usage: obj._create_model(session) and returns: study