code: def setup_class(self):
      self.dag = DAG(
          "test_dag",
          default_args={"owner": "airflow", "start_date": DEFAULT_DATE},
          schedule=INTERVAL,
      )
  
file_path: airflow/tests/operators/test_email.py
imports: from __future__ import annotations
  import datetime
  from unittest import mock
  import pytest
  from airflow.models.dag import DAG
  from airflow.operators.email import EmailOperator
  from airflow.utils import timezone
  from tests.test_utils.config import conf_vars
label_desc: Use image node_id 1 for calling the TestEmailOperator obj's underlying member method code with example usage: obj.setup_class() without return types