code: def setUp(self):
      root = os.path.join(os.path.dirname(__file__), "image_dataset")
      zipfilenames = [
          os.path.join(root, fn)
          for fn in ("zipped_images_1.zip", "zipped_images_2.zip")
      ]
      self.dataset = datasets.MultiZippedImageDataset(
          zipfilenames, dtype=self.dtype
      )
  
imports: import os
  import pickle
  import unittest
  import numpy
  from chainer import datasets
  from chainer.datasets import image_dataset
  from chainer import testing
label_desc: Use image node_id 1 for calling the TestMultiZippedImageDataset obj's underlying member method code with example usage: obj.setUp() without return types