code: def test_remove_factors(self):
      self.graph.add_edges_from([[("a", "b"), ("b", "c")]])
      phi1 = DiscreteFactor(["a", "b"], [2, 2], np.random.rand(4))
      phi2 = DiscreteFactor(["b", "c"], [2, 2], np.random.rand(4))
      self.graph.add_factors(phi1, phi2)
      self.graph.remove_factors(phi1)
      self.assertCountEqual(self.graph.factors, [phi2])
  
imports: import unittest
  import numpy
  from pgmpy.factors.discrete import DiscreteFactor
  from pgmpy.models import ClusterGraph
  from pgmpy.tests import help_functions
label_desc: Use image node_id 6 for calling the TestClusterGraphFactorOperations obj's underlying member method code with example usage: obj.test_remove_factors() without return types