code: public java.util.List<String> getNotificationTypes() {
          if (notificationTypes == null) {
              notificationTypes = new com.amazonaws.internal.SdkInternalList<String>();
          }
          return notificationTypes;
      }
docs: <p>
  The type of event that causes the notification to be sent. For more information about notification types
  supported by Amazon EC2 Auto Scaling, see <a>DescribeAutoScalingNotificationTypes</a>.
  </p>
  
  @return The type of event that causes the notification to be sent. For more information about notification types
  supported by Amazon EC2 Auto Scaling, see <a>DescribeAutoScalingNotificationTypes</a>.