docs: public List<File> findNRecentSnapshots(int n) throws IOException {
          List<File> files = Util.sortDataDir(snapDir.listFiles(), "snapshot", false);
          int i = 0;
          List<File> list = new ArrayList<File>();
          for (File f: files) {
              if (i==n)
                  break;
              i++;
              list.add(f);
          }
          return list;
      }