@NotNull
  public static PsiDirectory findOrCreateSubdirectory(@NotNull PsiDirectory parent, @NotNull String subdirName) {
    final PsiDirectory sub = parent.findSubdirectory(subdirName);
    return sub == null ? WriteAction.compute(() -> parent.createSubdirectory(subdirName)) : sub;
  }
@NotNull
  public static PsiDirectory findOrCreateSubdirectory(@NotNull PsiDirectory parent, @NotNull String subdirName)