@Deprecated
  static @NotNull <T extends PsiFileSystemItem> FileReferenceHelper getNotNullHelper(@NotNull T psiFileSystemItem) {
    FileReferenceHelper helper = getHelper(psiFileSystemItem);
    if (helper != null) {
      return helper;
    }
    FileReferenceHelper[] helpers = getHelpers();
    return helpers[helpers.length - 1];
  }
@Deprecated
  static @NotNull <T extends PsiFileSystemItem> FileReferenceHelper getNotNullHelper(@NotNull T psiFileSystemItem)