@NotNull
  public RootRemovalHandler createRootRemovalHandler() {
    return new RootRemovalHandler() {
      @Override
      public void onRootRemoved(@NotNull String rootUrl, @NotNull OrderRootType rootType, @NotNull LibraryEditor libraryEditor) {
      }
    };
  }
@NotNull
  public RootRemovalHandler createRootRemovalHandler()