code: def setUpClass(cls):
      cls.backend = "tifffile"
  
imports: from __future__ import annotations
  import os
  import unittest
  from typing import Any
  from unittest import skipUnless
  import numpy
  import torch
  from parameterized import parameterized
  from monai.config import PathLike
  from monai.data import DataLoader, Dataset
  from monai.data.wsi_reader import WSIReader
  from monai.transforms import Compose, LoadImaged, ToTensord
  from monai.utils import first, optional_import
  from monai.utils.enums import PostFix, WSIPatchKeys
  from tests.utils import assert_allclose, download_url_or_skip_test, skip_if_no_cuda, testing_data_config
label_desc: Use image node_id 1 for calling the TestTiffFile obj's underlying member method code with example usage: obj.setUpClass(cls) without return types