code: def test_discreteModelCrossValidate(self) -> None:
      discrete_model = DiscreteModel()
      with self.assertRaises(NotImplementedError):
          discrete_model.cross_validate(
              Xs_train=[[[0]]],
              Ys_train=[[1]],
              Yvars_train=[[1]],
              X_test=[[1]],
          )
  
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 7 for calling the DiscreteModelTest obj's underlying member method code with example usage: obj.test_discreteModelCrossValidate() without return types