code: def tearDown(self):
      del self.phi1
      del self.phi2
      del self.phi3
  
imports: import unittest
  import numpy
  import numpy.testing
  from scipy.special import beta
  from scipy.stats import multivariate_normal
  from pgmpy.factors.distributions import CustomDistribution
label_desc: Use image node_id 16 for calling the TestCustomDistributionMethods obj's underlying member method code with example usage: obj.tearDown() without return types