/**
  * @param null $validation_error_message
  */
 public function __construct($validation_error_message = NULL)
 {
     if (!$validation_error_message) {
         $validation_error_message = __("Please enter a valid email address.", "event_espresso");
     }
     parent::__construct($validation_error_message);
 }
 /**
  * @param null $validation_error_message
  */
 public function __construct($validation_error_message = NULL)
 {
     if (!$validation_error_message) {
         $validation_error_message = __("Please enter a valid credit card number", "event_espresso");
     }
     parent::__construct($validation_error_message);
 }