/**
  * Add events in $eventList1 that are not in $eventList2 to $errors array.
  * 
  * Works by reference on $errors by adding $message errors.
  * 
  * @param SQLI_CodeSniffer_EventList $eventList1
  * @param SQLI_CodeSniffer_EventList $eventList2
  * @param string $message
  * @param array $errors
  * @return void
  */
 protected static function _getMissingEvents($eventList1, $eventList2, $message, &$errors)
 {
     if (count($eventList1) == 0) {
         return;
     }
     foreach ($eventList1 as $event) {
         if (!$eventList2->hasEvent($event)) {
             $errors[$event->getLine()][$event->getColumn()][] = str_replace(':code', $event->getCode(), $message);
         }
     }
 }