Disabled refund emails for dokan sub order

gistfile1.txt

/**
 * Disabled refund emails for dokan sub order
 *
 * @param string $recipient
 * @param string $order
 *
 * @return mix
 */
function disable_refund_email_for_dokan_sub_order( $recipient, $order ) {
   if ( wp_get_post_parent_id( $order->get_id() ) ){
      return;
   } else {
      return $recipient;
   }
}
add_filter( 'woocommerce_email_recipient_customer_refunded_order', 'disable_refund_email_for_dokan_sub_order', 10, 2 );
add_filter( 'woocommerce_email_recipient_customer_partially_refunded_order', 'disable_refund_email_for_dokan_sub_order', 10, 2 );