@Nullable
  private static List<PropertyData> getProperties(@NotNull DiffContent content) {
    if (content instanceof SvnPropertiesDiffRequest.PropertyContent) {
      return ((SvnPropertiesDiffRequest.PropertyContent)content).getProperties();
    }
    return null;
  }
@Nullable
  private static List<PropertyData> getProperties(@NotNull DiffContent content)