code: @CheckForNull
      public UpdateSite getById(String id) {
          for (UpdateSite s : sites) {
              if (s.getId().equals(id)) {
                  return s;
              }
          }
          return null;
      }
docs: Gets {@link UpdateSite} by its ID.
  Used to bind them to URL.
  @param id ID of the update site to be retrieved
  @return Discovered {@link UpdateSite}. {@code null} if it cannot be found