result = (
    pl.scan_csv('large_sales_data.csv')
    .with_columns([
        (pl.col('sales') * pl.col('quantity') * (1 - 0.075)).alias('net_revenue')
    ])
    .filter(pl.col('status') == 'completed')
    .group_by('region')
    .agg(pl.col('net_revenue').sum())
    .collect()
)