EDD Currency Switcher - Sort the list of currencies

/**
 * Sorts the list of currencies displayed on the currency selector widget.
 *
 * 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 array currencies An array of currencies passed by the widget.
 * @param string widget_type The type of widget beind displayed (e.g. 'dropdown' or 'buttons').
 * @param string widget_title The widget title
 * @param string widget_template_name The template file that is going to be used to render the widget.
 * @return array
 */
function custom_sort_currencies($currencies, $widget_type, $widget_title, $widget_template_name) {
  // Sort the list of currencies before returning it
  $sorted_currencies = array(
    'USD' => $currencies['USD'],
    'GBP' => $currencies['GBP'],
    'EUR' => $currencies['EUR'],
  );

  return $sorted_currencies;
}
add_filter('edd_aelia_currencyswitcher_widget_currency_options', 'custom_sort_currencies', 10, 4);