class AllScenariosPageCollection extends PageCollection implements Visitable {

    public String getTotalDurationString() {
        ZonedDateTime earliestStartDateTime = getEarliestStartDateTime();
        ZonedDateTime latestEndDateTime = getLatestEndDateTime();

        // Return total runtime if no timestamps exist...
        if (earliestStartDateTime == null || latestEndDateTime == null) {
            return RenderingUtils.convertNanosecondsToTimeString(getTotalDuration());
        }

        // ...else return the calculated runtime.
        return RenderingUtils.convertNanosecondsToTimeString(
                ChronoUnit.NANOS.between(earliestStartDateTime, latestEndDateTime)
        );
    }

    public  AllScenariosPageCollection(final String pageTitle);

}