该错误是由于在使用DataFlowRunner时未指定服务账号导致的。需要在BeamRunPythonPipelineOperator的参数中添加“options”参数，并设置“service_account_email”属性为已授权执行任务的服务账号。以下是示例代码：

from airflow.providers.google.cloud.operators.dataflow import DataflowCreateJavaJobOperator, DataflowStartJavaJobOperator  
from airflow.utils.dates import days_ago  


yesterday = days_ago(1)  

default_args = {  
    'owner': 'airflow',  
    'depends_on_past': False,  
    'start_date': yesterday,  
    'email_on_failure': False,  
    'email_on_retry': False,  
    'retries': 0  
}  

options={  
    'runner': 'DataflowRunner',  
    'project': 'your-project-id',  
    'staging_location': 'gs://your/staging/location',  
    'temp_location': 'gs://your/temp/location',  
    'region': 'your-region-1',  
    'service_account_email': 'your-service-account-email',
}  

with DAG(  
    'your_dag_id',  
    default_args=default_args,  
    schedule_interval=None,  
) as dag:  
        
beam_run_python_pipeline = BeamRunPythonPipelineOperator(  
    task_id='your_task_id',  
    python_callable=your_python_function,  
    options=options  
)