Add text before regular price and sale price at the Woocommerce

gistfile1.txt

function bd_rrp_sale_price_html( $price, $product ) {
 
  if ( $product->is_on_sale() ) :
    $has_sale_text = array(
      '<del>' => '<del>RRP: ',
      '<ins>' => '<br>Sale Price: <ins>'
    );
    $return_string = str_replace(array_keys( $has_sale_text ), array_values( $has_sale_text ), $price);
 
  else :
    $retun_string = 'RRP: ' . $price;
  endif;
 
  return $return_string;
}
add_filter( 'woocommerce_get_price_html', 'bd_rrp_sale_price_html', 100, 2 );

This is exactly what I need, but the code doesn't work (anymore). Could you perhaps update it? Would help me a lot and I would really appreciate it!

RRP: is showing, but Sale Price: isn't.

RRP: is only showing when a product doesn't have a sales price.