text: from datetime import datetime
  from time import sleep
  
  from airflow import DAG
  from airflow.operators.dummy_operator import DummyOperator
  from airflow.operators.python import PythonOperator
  from utils.date_utils import LOCAL_TZ
  
  
  def say_something(*args, **kwargs):
      print("Estou dormindo agora")
      sleep(60)
      print(args)
  
  
  dag = DAG(
      dag_id="demo02",
      default_args={
          "owner": "rodrigo.coelho",
          "start_date": datetime(2021, 12, 1, tzinfo=LOCAL_TZ),
      },
      schedule_interval="@daily",
      tags=["demo", "python", "analytics.engineering"],
  )
  
  jobs = {}
  
  jobs["start"] = DummyOperator(task_id="start", dag=dag)
  jobs["stop"] = DummyOperator(task_id="stop", dag=dag)
  jobs["hello"] = PythonOperator(
      task_id="hello",
      python_callable=say_something,
      op_args="hello",
      dag=dag
  )
  
  jobs["hi"] = PythonOperator(task_id="hi", python_callable=say_something, op_args="hello", dag=dag)
  
  jobs["start"].set_downstream(jobs["hello"])
  
  jobs["stop"].set_upstream(jobs["hello"])
  
  jobs["hi"].set_upstream(jobs["start"])  # <<
  jobs["hi"].set_downstream(jobs["stop"])  # >>
  