private static boolean isJupyterFile(@NotNull PsiElement element) {
    if (!(element instanceof PsiFile)) {
      return false;
    }
    final VirtualFile virtualFile = ((PsiFile)element).getVirtualFile();
    return virtualFile != null &&
           Objects.equals(virtualFile.getExtension(), "ipynb");
  }
private static boolean isJupyterFile(@NotNull PsiElement element)