code: def test_cpds_simple(self):
      self.assertEqual("x1", self.cpd1.variable)
      self.assertEqual(4, self.cpd1.variance)
      self.assertEqual([1], self.cpd1.mean)
  
      self.model.add_cpds(self.cpd1)
      cpd = self.model.get_cpds("x1")
      self.assertEqual(cpd.variable, self.cpd1.variable)
      self.assertEqual(cpd.variance, self.cpd1.variance)
      self.assertEqual(cpd.mean, self.cpd1.mean)
  
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 2 for calling the TestLGBNMethods obj's underlying member method code with example usage: obj.test_cpds_simple() without return types