example-dag.py

from airflow.models import DAG
from airflow.utils.dates import days_ago
from airflow.operators.dummy import DummyOperator
from airflow.operators.python_operator import PythonOperator


def foo(**context):
    print(context['ds_nodash'])


with DAG(
    dag_id="my_test",
    schedule_interval=None,
    start_date=days_ago(3),
    catchup=False
) as dag:
    op1 = DummyOperator(task_id="t1")
    op2 = PythonOperator(task_id="t2", python_callable=foo)

    op1 >> op2