code: def test_unary_callable_dict(self):
      dataset = tabular.from_data(
          (("a", "b"), lambda i: {"a": i * i, "b": -i}), size=10
      )
  
      self.assertIsInstance(dataset, chainer.dataset.TabularDataset)
      self.assertEqual(len(dataset), 10)
      self.assertEqual(dataset.keys, ("a", "b"))
      self.assertEqual(dataset.mode, dict)
  
      output = dataset.slice[[1, 3]].fetch()
      np.testing.assert_equal(output, {"a": [1, 9], "b": [-1, -3]})
      for out in output.values():
          self.assertIsInstance(out, list)
  
imports: import unittest
  import numpy
  import chainer
  from chainer.dataset import tabular
  from chainer import testing
label_desc: Use image node_id 7 for calling the TestFromData obj's underlying member method code with example usage: obj.test_unary_callable_dict() without return types