code: def test_check_model2(self):
      self.graph.add_edges_from(
          [(("a", "b"), ("a", "c")), (("a", "c"), ("a", "d"))]
      )
  
      phi1 = DiscreteFactor(["a", "b"], [1, 2], np.random.rand(2))
      phi2 = DiscreteFactor(["a", "c"], [3, 3], np.random.rand(9))
      phi3 = DiscreteFactor(["a", "d"], [4, 4], np.random.rand(16))
      self.graph.add_factors(phi1, phi2, phi3)
      self.assertRaises(ValueError, self.graph.check_model)
      self.graph.remove_factors(phi2)
      phi2 = DiscreteFactor(["a", "c"], [1, 3], np.random.rand(3))
      self.graph.add_factors(phi2)
      self.assertRaises(ValueError, self.graph.check_model)
      self.graph.remove_factors(phi3)
  
      phi3 = DiscreteFactor(["a", "d"], [1, 4], np.random.rand(4))
      self.graph.add_factors(phi3)
      self.assertTrue(self.graph.check_model())
  
imports: import unittest
  import numpy
  from pgmpy.factors.discrete import DiscreteFactor
  from pgmpy.models import ClusterGraph
  from pgmpy.tests import help_functions
label_desc: Use image node_id 6 for calling the TestClusterGraphMethods obj's underlying member method code with example usage: obj.test_check_model2() without return types