code: def heartbeat_healthy():
      # case-1: healthy scheduler status
      last_heartbeat = timezone.utcnow()
      job = Job(
          state="running",
          latest_heartbeat=last_heartbeat,
      )
      SchedulerJobRunner(job=job)
      with create_session() as session:
          session.add(job)
      yield "healthy", last_heartbeat.isoformat()
      with create_session() as session:
          session.query(Job).filter(
              Job.job_type == "SchedulerJob",
              Job.state == "running",
              Job.latest_heartbeat == last_heartbeat,
          ).delete()
  
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 4 for calling a global function with example usage: heartbeat_healthy() without return types