code: def test_features_to_extract_param():
      assert (
          DatetimeFeatures(features_to_extract=None).features_to_extract
          is None
      )
      assert DatetimeFeatures(
          features_to_extract=["year"]
      ).features_to_extract == ["year"]
      assert (
          DatetimeFeatures(
              features_to_extract="all"
          ).features_to_extract
          == "all"
      )
  
imports: import numpy
  import pandas
  import pytest
  from sklearn.exceptions import NotFittedError
  from sklearn.pipeline import Pipeline
  from feature_engine.datetime import DatetimeFeatures
  from feature_engine.datetime._datetime_constants import FEATURES_DEFAULT, FEATURES_SUFFIXES, FEATURES_SUPPORTED
label_desc: Use image node_id 4 for calling a global function with example usage: test_features_to_extract_param() without return types