@NotNull
  @Override
  public LibraryTable.ModifiableModel getModifiableProjectLibrariesModel() {
    if (myLibrariesModel != null) return myLibrariesModel;
    LibraryTable libraryTable = LibraryTablesRegistrar.getInstance().getLibraryTable(myProject);
    return myLibrariesModel = ((ProjectLibraryTableBridge)libraryTable).getModifiableModel(getActualStorageBuilder());
  }
@NotNull
  @Override
  public LibraryTable.ModifiableModel getModifiableProjectLibrariesModel()