code: def test_set_keys_single_tuple_index(self):
      self.dataset.keys = self.iterable((1,))
      self.assertEqual(self.dataset.keys, ("item1",))
      self.assertEqual(self.dataset[2], ("item1(2)",))
  
imports: import numpy
  import unittest
  from chainercv.chainer_experimental.datasets.sliceable import GetterDataset
  from chainercv.utils import testing
label_desc: Use image node_id 7 for calling the TestGetterDataset obj's underlying member method code with example usage: obj.test_set_keys_single_tuple_index() without return types