How to use the flowetl.operators.extract_from_view_operator.ExtractFromViewOperator function in flowetl

macros = dict(**additional_macros)
    if source_table is not None:
        macros["source_table"] = source_table

    with DAG(
        dag_id=dag_id,
        schedule_interval=schedule_interval,
        default_args=args,
        user_defined_macros=macros,
        params=dict(cdr_type=cdr_type),
    ) as dag:
        if staging_view_sql is not None and source_table is not None:
            create_staging_view = CreateStagingViewOperator(
                task_id="create_staging_view", sql=staging_view_sql,
            )
            extract = ExtractFromViewOperator(
                task_id="extract", sql=extract_sql, pool="postgres_etl"
            )
        elif filename is not None and len(fields) > 0:
            create_staging_view = CreateForeignStagingTableOperator(
                task_id="create_staging_view",
                program=program,
                filename=filename,
                fields=fields,
                null=null,
                header=header,
                delimiter=delimiter,
                quote=quote,
                escape=escape,
                encoding=encoding,
            )
            extract = ExtractFromForeignTableOperator(