code: def setUp(self):
      mean = np.array([0, 0])
      covariance = np.array([[-1, 0.8], [0.8, 3]])
      self.test_model = JGD(["x", "y"], mean, covariance)
      position = [0, 0]
      momentum = [-2, 1]
      self.test_with_grad_log = ModifiedEuler(
          model=self.test_model,
          position=position,
          momentum=momentum,
          stepsize=0.5,
          grad_log_pdf=GradLogPDFGaussian,
          grad_log_position=None,
      )
      grad_log_position, _ = GradLogPDFGaussian(
          position, self.test_model
      ).get_gradient_log_pdf()
      self.test_without_grad_log = ModifiedEuler(
          model=self.test_model,
          position=position,
          momentum=momentum,
          stepsize=0.3,
          grad_log_pdf=GradLogPDFGaussian,
          grad_log_position=grad_log_position,
      )
  
imports: import unittest
  import numpy
  from pgmpy.factors.distributions import GaussianDistribution
  from pgmpy.sampling import LeapFrog, ModifiedEuler, GradLogPDFGaussian
label_desc: Use image node_id 1 for calling the TestModifiedEuler obj's underlying member method code with example usage: obj.setUp() without return types