code: def test_univariate_data_step():
      y = load_airline()
      # Test that prior test works for with univariate dataset
      y_train, y_test = temporal_train_test_split(y)
      pipe = DateTimeFeatures(
          manual_selection=["year", "second_of_minute"],
          keep_original_columns=True,
      )
      test_univariate_data = pipe.fit_transform(y_train)
      return test_univariate_data
  
imports: import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
  from sktime.datasets import load_airline, load_longley, load_PBS_dataset
  from sktime.split import temporal_train_test_split
  from sktime.tests.test_switch import run_test_for_class
  from sktime.transformations.series.date import DateTimeFeatures
  from sktime.utils._testing.hierarchical import _make_hierarchical
label_desc: Use image node_id 13 for calling a global function with example usage: test_univariate_data_step() and returns: test_univariate_data