code: def test_frequency_specified(self):
      dt_idx = pd.to_datetime(
          [
              "2014-01-01 00:00:12",
              "2014-01-01 00:00:14",
              "2014-01-01 00:00:16",
              "2014-01-01 00:00:18",
          ]
      )
      test_series = pd.DataFrame(
          np.arange(4), index=dt_idx, columns=["value"]
      ).sort_index()
      regularized_data = regularization.regularize_series(
          test_series, frequency=pd.DateOffset(seconds=2)
      )
      self.assertEqual(
          regularized_data.index.freq, pd.DateOffset(seconds=2)
      )
  
file_path: probability/tensorflow_probability/python/sts/regularization_test.py
imports: import datetime
  from absl.testing import parameterized
  import numpy
  import pandas
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.sts import regularization
label_desc: Use image node_id 3 for calling the RegularizationTest obj's underlying member method code with example usage: obj.test_frequency_specified() without return types