code: def test_in_sample_fold(self):
      tracer = tracing_reducer.TracingReducer()
      fake_kernel = test_fixtures.TestTransitionKernel()
      trace, final_state, kernel_results = sample_fold(
          num_steps=3,
          current_state=0.0,
          kernel=fake_kernel,
          reducer=tracer,
          seed=test_util.test_seed(),
      )
      trace, final_state, kernel_results = self.evaluate(
          [trace, final_state, kernel_results]
      )
      self.assertAllEqual([1, 2, 3], trace[0])
      self.assertAllEqual([1, 2, 3], trace[1].counter_1)
      self.assertAllEqual([2, 4, 6], trace[1].counter_2)
      self.assertEqual(3, final_state)
      self.assertEqual(3, kernel_results.counter_1)
      self.assertEqual(6, kernel_results.counter_2)
  
file_path: probability/tensorflow_probability/python/experimental/mcmc/tracing_reducer_test.py
imports: import tensorflow.compat.v2
  from tensorflow_probability.python.experimental.mcmc import tracing_reducer
  from tensorflow_probability.python.experimental.mcmc.internal import test_fixtures
  from tensorflow_probability.python.experimental.mcmc.sample_fold import sample_fold
  from tensorflow_probability.python.internal import tensorshape_util
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 2 for calling the TracingReducerTest obj's underlying member method code with example usage: obj.test_in_sample_fold() without return types