code: public static @Nullable Date mostRecent(@Nullable Page @NotNull... pages) {
      Date[] dates = new Date[pages.length];
      for (int i = 0; i < pages.length; i++) {
        dates[i] = get(pages[i]);
      }
      return mostRecent(dates);
    }
docs: Finds the most recent modification date of all specified pages
  @param pages multiple cq pages
  @return the most recent date (or null if none of the pages has a modification date)