text: import os
  from airflow import DAG
  from airflow.operators.bash_operator import BashOperator
  from datetime import datetime, timedelta
  
  default_args = {
      'owner': 'airflow',
      'depends_on_past': False,
      'start_date': datetime(2018, 11, 2),
      'email': ['airflow@example.com'],
      'email_on_failure': False,
      'email_on_retry': False,
      'retries': 0,
      'retry_delay': timedelta(minutes=5),
      # 'queue': 'bash_queue',
      # 'pool': 'backfill',
      # 'priority_weight': 10,
      # 'end_date': datetime(2016, 1, 1),
  }
  
  dag = DAG('comet_bqload', max_active_runs=1, catchup=False, default_args=default_args, schedule_interval=None)
  
  COMET_SPARK_CMD = os.environ.get('COMET_SPARK_CMD', '')
  
  templated_command = COMET_SPARK_CMD + """ {{ dag_run.conf['command'] }}"""
  
  t1 = BashOperator(
      task_id='comet_bqload',
      bash_command=templated_command,
      dag=dag)
  