code: def test_cost(self):
      self.assertEqual(self.elimination_order.cost("grade"), 3)
      self.assertEqual(self.elimination_order.cost("reco"), 1)
      self.assertEqual(self.elimination_order.cost("intel"), 3)
  
imports: from unittest import TestCase
  import numpy
  import pandas
  from pgmpy.inference.EliminationOrder import BaseEliminationOrder, MinFill, MinNeighbors, MinWeight, WeightedMinFill
  from pgmpy.models import BayesianNetwork
label_desc: Use image node_id 2 for calling the TestMinNeighbors obj's underlying member method code with example usage: obj.test_cost() without return types