code: def tearDown(self):
      del self.test_model
      del self.test_with_grad_log
      del self.test_without_grad_log
  
imports: import unittest
  import numpy
  from pgmpy.factors.distributions import GaussianDistribution
  from pgmpy.sampling import LeapFrog, ModifiedEuler, GradLogPDFGaussian
label_desc: Use image node_id 4 for calling the TestLeapFrog obj's underlying member method code with example usage: obj.tearDown() without return types