code: def test_markov_model(self):
      self.expected_markov_file = """MARKOV
  3
  2 2 3
  2
  2 0 1
  3 0 1 2
  
  4
  4.0 2.4 1.0 0.0
  12
  2.25 3.25 3.75 0.0 0.0 10.0 1.875 4.0 3.333 2.0 2.0 3.4"""
      self.assertEqual(
          str(self.markovwriter.__str__()),
          str(self.expected_markov_file),
      )
  
imports: import unittest
  import networkx
  import numpy
  from pgmpy import config
  from pgmpy.factors.discrete import DiscreteFactor, TabularCPD
  from pgmpy.models import BayesianNetwork, MarkovNetwork
  from pgmpy.readwrite import UAIReader, UAIWriter
label_desc: Use image node_id 3 for calling the TestUAIWriterTorch obj's underlying member method code with example usage: obj.test_markov_model() without return types