code: def testStochasticVolatilityModelLogSP500(self):
      num_train_points = 2516
  
      dataset = data.sp500_log_returns()
  
      self.assertEqual(
          (num_train_points,), dataset["centered_returns"].shape
      )
      self.assertAllClose(
          0.0, np.mean(dataset["centered_returns"]), atol=1e-5
      )
  
file_path: probability/spinoffs/inference_gym/inference_gym/internal/data_test.py
imports: import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import test_util
  from inference_gym.internal import data
  from inference_gym.internal import test_util
label_desc: Use image node_id 4 for calling the DataTest obj's underlying member method code with example usage: obj.testStochasticVolatilityModelLogSP500() without return types