[Coupon admin email] Add the used coupon code in the email to the shop admin #woocommerce

woocommerce_email_before_order_table.php

<?php
add_action( 'woocommerce_email_before_order_table', 'dev_maybe_add_used_coupon_code_admin_emails', 20, 4 );
  
function dev_maybe_add_used_coupon_code_admin_emails( $order, $sent_to_admin, $plain_text, $email ) {
   if ( $sent_to_admin !== false ) {
	 
	 $coupon_codes = $order->get_used_coupons();
	 if(!empty($coupon_codes)):
		 foreach( $coupon_codes as $coupon_code ):

			// Get the WC_Coupon object
			$coupon = new WC_Coupon($coupon_code);

			$coupon_used_code = $coupon->get_code(); // Get coupon code
			$discount_type = $coupon->get_discount_type(); // Get coupon discount type
			$coupon_amount = $coupon->get_amount(); // Get coupon amount
	 		
	 	 	echo '<p class="email-coupon-used"><b>Voor deze bestelling is gebruik gemaakt van een kortingscode:</b><br/>';
	 		echo 'Kortingscode: '. $coupon_used_code .'<br/>';
	 		echo 'Korting aantal: '. $coupon_amount .'<br/>';
	 		echo 'Kortingscode type: '. $discount_type .'</p>';
	 
		endforeach;
	 endif;
   }
}

add_filter( 'woocommerce_get_order_item_totals', 'dev_coupon_filter_woocommerce_get_order_item_totals', 10, 3 );
function dev_coupon_filter_woocommerce_get_order_item_totals( $total_rows, $order, $tax_display ) {
  // Exit if there is no coupons applied
  if ( sizeof ( $order->get_coupon_codes() ) == 0 ) return $total_rows;

  $coupons = [];
  foreach ( $order->get_items('coupon') as $coupon ) {
	$coupons[] = $coupon->get_code();
  }   

  // Overwrite
  if(count($coupons) > 0 && isset($total_rows['discount'])){
	$total_rows['discount']['label'] = __('Discount:', 'woocommerce') . " <span style='font-size:12px;'>" . implode(" ", $coupons) . "</span>";
  }

  return $total_rows;
}