code: def test_feature_importance(self):
      selector = FeatureSelector()
      self.assertIsNone(selector.feature_importances_)
  
      y = pd.Series(np.random.binomial(1, 0.5, 1000))
      X = pd.DataFrame(index=list(range(1000)))
  
      X["irr1"] = np.random.normal(0, 1, 1000)
      X["rel1"] = y
  
      selector.fit(X, y)
  
      self.assertEqual(selector.feature_importances_.shape, (2,))
  
file_path: tsfresh/tests/units/transformers/test_feature_selector.py
imports: from builtins import range
  from unittest import TestCase
  import numpy
  import pandas
  from tsfresh.transformers.feature_selector import FeatureSelector
label_desc: Use image node_id 6 for calling the FeatureSelectorTestCase obj's underlying member method code with example usage: obj.test_feature_importance() without return types