code: def tearDown(self):
      del self.graph
  
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 8 for calling the TestJunctionTreeCreation obj's underlying member method code with example usage: obj.tearDown() without return types