@Nullable
  private static DownloadableLibraryDescription getDownloadableDescription(CustomLibraryDescription libraryDescription) {
    final DownloadableLibraryType type = libraryDescription.getDownloadableLibraryType();
    if (type != null) return type.getLibraryDescription();
    if (libraryDescription instanceof OldCustomLibraryDescription) {
      return ((OldCustomLibraryDescription)libraryDescription).getDownloadableDescription();
    }
    return null;
  }
@Nullable
  private static DownloadableLibraryDescription getDownloadableDescription(CustomLibraryDescription libraryDescription)