code: def test_find_by_trial_and_key(session: Session) -> None:
      study = StudyModel(study_id=1, study_name="test-study")
      trial = TrialModel(study_id=study.study_id)
  
      session.add(
          TrialSystemAttributeModel(
              trial_id=trial.trial_id, key="sample-key", value_json="1"
          )
      )
      session.commit()
  
      attr = TrialSystemAttributeModel.find_by_trial_and_key(
          trial, "sample-key", session
      )
      assert attr is not None
      assert "1" == attr.value_json
      assert (
          TrialSystemAttributeModel.find_by_trial_and_key(
              trial, "not-found", session
          )
          is None
      )
  
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 TestTrialSystemAttributeModel obj's underlying member method code with example usage: obj.test_find_by_trial_and_key(session) without return types