code: def test_fill_in_edges(self):
      self.assertEqual(
          list(self.elimination_order.fill_in_edges("diff")), []
      )
  
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 3 for calling the TestBaseElimination obj's underlying member method code with example usage: obj.test_fill_in_edges() without return types