docs: private String getDefaultVersion(Set<String> keys, String appName) {
      SortedSet<String> listOfApps = new TreeSet<String>();
      for (String key : keys) {
        if (key.split(":")[0].contentEquals(appName)) {
          listOfApps.add(key);
        }
      }
      return listOfApps.size() > 0 ? listOfApps.last() : null;
    }