code: public static Iterable<BoxFileVersionRetention.Info> getAll(BoxAPIConnection api, String ... fields) {
          return getRetentions(api, new QueryFilter(), fields);
      }
docs: Retrieves all file version retentions.
  @param api the API connection to be used by the resource.
  @param fields the fields to retrieve.
  @return an iterable contains information about all file version retentions.