code: def tearDown(self):
      config.set_backend("numpy")
  
imports: import unittest
  from pgmpy import config
  from pgmpy.factors.discrete import DiscreteFactor, TabularCPD
  from pgmpy.inference import ApproxInference, VariableElimination
  from pgmpy.models import DynamicBayesianNetwork
  from pgmpy.utils import get_example_model
label_desc: Use image node_id 5 for calling the TestApproxInferenceBNTorch obj's underlying member method code with example usage: obj.tearDown() without return types