code: def teardown_class(cls):
      del cls.dag
      del cls.hook
  
imports: from __future__ import annotations
  from moto import mock_rds
  from airflow.models import DAG
  from airflow.providers.amazon.aws.hooks.rds import RdsHook
  from airflow.providers.amazon.aws.sensors.rds import RdsBaseSensor, RdsDbSensor, RdsExportTaskExistenceSensor, RdsSnapshotExistenceSensor
  from airflow.providers.amazon.aws.utils.rds import RdsDbType
  from airflow.utils import timezone
label_desc: Use image node_id 2 for calling the TestRdsExportTaskExistenceSensor obj's underlying member method code with example usage: obj.teardown_class(cls) without return types