code: def test_mean_and_std(
      self, values, ddof, expected_mean, expected_std
  ):
      actual_mean, actual_std = confidence_intervals_util.mean_and_std(
          values, ddof
      )
      self.assertEqual(expected_mean, actual_mean)
      self.assertEqual(expected_std, actual_std)
  
file_path: model-analysis/tensorflow_model_analysis/evaluators/confidence_intervals_util_test.py
imports: from absl.testing import absltest
  from absl.testing import parameterized
  import apache_beam
  from apache_beam.testing import util
  import numpy
  from numpy import testing
  from tensorflow_model_analysis.evaluators import confidence_intervals_util
  from tensorflow_model_analysis.metrics import binary_confusion_matrices
  from tensorflow_model_analysis.metrics import metric_types
label_desc: Use image node_id 1 for calling the ConfidenceIntervalsUtilTest obj's underlying member method code with example usage: obj.test_mean_and_std(values, ddof, expected_mean, expected_std) without return types