WooCommerce - Remove "Free" label from shipping optiosn

<?php
  // code to remove "(Free)" from free shipping labels
  // snippet goes in functions.php for your child theme
  add_filter( 'woocommerce_cart_shipping_method_full_label', 'my_label', 8);
  function my_label($label) {
    return str_replace('(Free)', 'abcd', $label);
  }