code: def test_add_variables_from(self, add_var):
      model = MC()
      model.add_variables_from(self.variables, self.card)
      calls = [call(model, *p) for p in zip(self.variables, self.card)]
      add_var.assert_has_calls(calls)
  
imports: import sys
  import unittest
  import numpy
  from mock import call, patch
  from pandas import DataFrame
  from pgmpy.factors.discrete import State
  from pgmpy.models import MarkovChain
label_desc: Use image node_id 15 for calling the TestMarkovChain obj's underlying member method code with example usage: obj.test_add_variables_from(add_var) without return types