code: def tearDown(self):
      del self.m1
      del self.d1
  
file_path: pgmpy/pgmpy/tests/test_estimators/test_ParameterEstimator.py
imports: import unittest
  from numpy import NaN
  from pandas import DataFrame
  from pgmpy.estimators import ParameterEstimator
  from pgmpy.models import BayesianNetwork
label_desc: Use image node_id 4 for calling the TestParameterEstimator obj's underlying member method code with example usage: obj.tearDown() without return types