docstr: Determines slack_period based on num devices attached to iterator.
docstr_tok: ["Determines","slack_period","based","on","num","devices","attached","to","iterator","."]
code: def testPrefetchWithSlackOption(self):
      """Determines slack_period based on num devices attached to iterator."""
      dataset = dataset_ops.Dataset.range(10)
      dataset = dataset.prefetch(1)
      options = options_lib.Options()
      options.experimental_slack = True
      dataset = dataset.with_options(options)
      multi_device_iterator = (
          multi_device_iterator_ops.MultiDeviceIterator(
              dataset, [self._devices[1], self._devices[2]]
          )
      )
      self.evaluate(multi_device_iterator.initializer)
      for i in range(0, 10, 2):
          elem_on_1, elem_on_2 = multi_device_iterator.get_next()
          self.assertEqual(i, self.evaluate(elem_on_1))
          self.assertEqual(i + 1, self.evaluate(elem_on_2))
      with self.assertRaises(errors.OutOfRangeError):
          elem_on_1, elem_on_2 = multi_device_iterator.get_next()
          self.evaluate(elem_on_1)
          self.evaluate(elem_on_2)
  
file_path: tensorflow/tensorflow/python/data/experimental/kernel_tests/prefetch_with_slack_test.py
imports: from absl.testing import parameterized
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import multi_device_iterator_ops
  from tensorflow.python.data.ops import options
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import errors
  from tensorflow.python.platform import test
label_desc: Use image node_id 2 for calling the PrefetchWithSlackTest obj's underlying member method code with example usage: obj.testPrefetchWithSlackOption() without return types