Airflow - AirflowTimetableInvalid: Exactly 5, 6 or 7 columns has to be specified for iterator expression.

 

from airflow.decorators import (
    dag,
    task,
)

from pendulum import datetime


@dag(
    schedule="@none",
    start_date=datetime(2025, 1, 1),
    catchup=False,
    default_args={
        "retries": 2,
    },
    tags=["test"],
)
def test_connection():
    @task()
    def print_conn_string():
        import os

        conn_string = os.getenv("AIRFLOW_CONN_MYDB")
        print(f"Connection string: {conn_string}")

    print_conn_string()

test_connection()

Got DAG Import Error:

AirflowTimetableInvalid: Exactly 5, 6 or 7 columns has to be specified for iterator expression.

 

To fix it, just delete the line with red background, or change it to 'schedule=None'.