code: def test_multiclass_selection(self):
      augmenter = RelevantFeatureAugmenter(
          column_value="val",
          column_id="id",
          column_sort="sort",
          column_kind="kind",
          multiclass=True,
          n_significant=3,
      )
  
      df, y = self.create_test_data_sample_with_multiclass_target()
      X = pd.DataFrame(index=np.unique(df.id))
  
      augmenter.set_timeseries_container(df)
      fit_transformed_X = augmenter.fit_transform(X, y)
  
      self.assertEqual(len(fit_transformed_X.columns), 4)
  
imports: import mock
  import numpy
  import pandas
  from sklearn import model_selection
  from sklearn.ensemble import RandomForestClassifier
  from sklearn.pipeline import Pipeline
  from tests.fixtures import DataTestCase, warning_free
  from tsfresh.feature_extraction import MinimalFCParameters
  from tsfresh.transformers.relevant_feature_augmenter import RelevantFeatureAugmenter
label_desc: Use image node_id 9 for calling the RelevantFeatureAugmenterTestCase obj's underlying member method code with example usage: obj.test_multiclass_selection() without return types