code: def heartbeat_not_running():
      # case-3: unhealthy scheduler status - scenario 2 (no running SchedulerJob)
      with create_session() as session:
          session.query(Job).filter(
              Job.job_type == "SchedulerJob",
              Job.state == "running",
          ).delete()
      yield "unhealthy", None
  
imports: from __future__ import annotations
  import datetime
  import json
  import pytest
  from airflow.jobs.job import Job
  from airflow.jobs.scheduler_job_runner import SchedulerJobRunner
  from airflow.utils import timezone
  from airflow.utils.session import create_session
  from airflow.www import app
  from tests.test_utils.asserts import assert_queries_count
  from tests.test_utils.config import conf_vars
  from tests.test_utils.www import check_content_in_response, check_content_not_in_response
label_desc: Use image node_id 6 for calling a global function with example usage: heartbeat_not_running() without return types