code: def test_not_implemented_methods(self):
      self.assertRaises(ValueError, self.model.get_cardinality, "x1")
      self.assertRaises(
          NotImplementedError, self.model.fit, [[1, 2, 3], [1, 5, 6]]
      )
      self.assertRaises(
          NotImplementedError,
          self.model.predict,
          [[1, 2, 3], [1, 5, 6]],
      )
      self.assertRaises(NotImplementedError, self.model.to_markov_model)
      self.assertRaises(
          NotImplementedError,
          self.model.is_imap,
          [[1, 2, 3], [1, 5, 6]],
      )
  
file_path: pgmpy/pgmpy/tests/test_models/test_LinearGaussianBayesianNetwork.py
imports: import unittest
  import numpy
  import numpy.testing
  from pgmpy.factors.continuous import LinearGaussianCPD
  from pgmpy.factors.discrete import TabularCPD
  from pgmpy.models import LinearGaussianBayesianNetwork
label_desc: Use image node_id 6 for calling the TestLGBNMethods obj's underlying member method code with example usage: obj.test_not_implemented_methods() without return types