code: def test_discrete_model_feature_importances(self) -> None:
      discrete_model = DiscreteModel()
      with self.assertRaises(NotImplementedError):
          discrete_model.feature_importances()
  
file_path: Ax/ax/models/tests/test_discrete.py
imports: import numpy
  from ax.models.discrete_base import DiscreteModel
  from ax.utils.common.testutils import TestCase
label_desc: Use image node_id 3 for calling the DiscreteModelTest obj's underlying member method code with example usage: obj.test_discrete_model_feature_importances() without return types