How To Complete WooCommerce Order Automatically After Successful Payment

Code To Copy and pase as PHP sinppet:

add_action('woocommerce_thankyou','custom_woocommerce_auto_complete_order');
function   custom_woocommerce_auto_complete_order( $order_id ) {  
                if ( ! $order_id ) {return;}            
                $order = wc_get_order( $order_id );    
                $order->update_status( 'completed' ); 
}