WooCommerce Tax Display - Product prices fixed only for EU

/**
 * Aelia Tax Display by Country for WooCommerce.
 * Enabled the "keep product prices fixed" option only when the customer is in
 * the EU.
 *
 * HOW TO USE THIS CODE
 * Add the code to the bottom of your theme's functions.php file, and it
 * will run automatically. For more information: https://www.skyverge.com/blog/add-custom-code-to-wordpress/
 *
 * GPL DISCLAIMER
 * Because this code program is free of charge, there is no warranty for it, to the extent permitted by applicable law.
 * Except when otherwise stated in writing the copyright holders and/or other parties provide the program "as is"
 * without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of
 * merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the program
 * is with you. should the program prove defective, you assume the cost of all necessary servicing, repair or correction.
 *
 * Need a consultation, or assistance to customise this code? Find us on Codeable: https://aelia.co/hire_us
 *
 * @param bool keep_prices_fixed
 * @return bool
 */
add_filter('wc_aelia_tdbc_keep_prices_fixed', function($keep_prices_fixed) {
  // Get customer's billing country. You can replace it with the shipping country,
  // if that's the information used to calculate taxes
  $customer_country = WC()->customer->get_billing_country();
  // Only keep prices fixed for EU customers
  return in_array($customer_country, WC()->countries->get_european_union_countries());
});