How to reorder checkout fields on WooCommerce checkout billing or shipping firleds

functions.php

add_filter( "woocommerce_checkout_fields", "my_reordering_checkout_fields", 15, 1 );
function my_reordering_checkout_fields( $fields ) {
  ## ---- Billing Fields ---- ##
  // Set the order of the fields
  $billing_order = array(
  'billing_first_name',
  'billing_last_name',
  'billing_email',
  'billing_phone',
  'billing_company',
  'billing_address_1',
  'billing_address_2',
  'billing_postcode',
  'billing_city',
  'billing_state',
  'billing_country'

  );
  $count = 0;
 
  $priority = 10;
 
  // Updating the 'priority' argument
  foreach($billing_order as $field_name){
    $count++;
    $fields['billing'][$field_name]['priority'] = $count * $priority;
  }
  // Change the CSS class
  $fields['billing']['billing_email']['class'] = array('form-row-first');
  $fields['billing']['billing_phone']['class'] = array('form-row-last');
  $fields['billing']['billing_postcode']['class'] = array('form-row-first');
  $fields['billing']['billing_city']['class'] = array('form-row-last');
  ## ---- Return the new fields order ---- ##
  return $fields;
 
}