code: def test_moralize(self):
      moral_graph = self.graph.moralize()
      self.assertListEqual(
          hf.recursive_sorted(moral_graph.edges()),
          [["diff", "grade"], ["diff", "intel"], ["grade", "intel"]],
      )
  
imports: import unittest
  import networkx
  import numpy
  import pgmpy.tests.help_functions
  from pgmpy.base import DAG, PDAG
label_desc: Use image node_id 3 for calling the TestDAGMoralization obj's underlying member method code with example usage: obj.test_moralize() without return types