code: def test_base(self):
      self.assertEqual(
          self.dataset[0], ("item0(0)", "item1(0)", "item2(0)")
      )
  
imports: import numpy
  import six
  import unittest
  from chainercv.chainer_experimental.datasets.sliceable import SliceableDataset
  from chainercv.utils import testing
label_desc: Use image node_id 2 for calling the TestSliceableDataset obj's underlying member method code with example usage: obj.test_base() without return types