code: def tearDown(self):
      del self.factor1
      del self.factor2
      del self.factor3
      del self.factor4
      del self.factor5
  
      del self.graph1
      del self.graph2
      del self.graph3
      del self.graph4
  
imports: import unittest
  import numpy
  from pgmpy.factors.discrete import DiscreteFactor
  from pgmpy.models import JunctionTree
  from pgmpy.tests import help_functions
label_desc: Use image node_id 4 for calling the TestJunctionTreeMethods obj's underlying member method code with example usage: obj.tearDown() without return types