code: def setUp(self):
      self.d1 = pd.DataFrame(
          data={
              "A": [0, 0, 1],
              "B": [0, 1, 0],
              "C": [1, 1, 0],
              "D": ["X", "Y", "Z"],
          }
      )
      self.m1 = BayesianNetwork([("A", "C"), ("B", "C"), ("D", "B")])
      self.m2 = BayesianNetwork([("C", "A"), ("C", "B"), ("A", "D")])
  
      # data_link - "https://www.kaggle.com/c/titanic/download/train.csv"
      self.titanic_data = pd.read_csv(
          "pgmpy/tests/test_estimators/testdata/titanic_train.csv"
      )
      self.titanic_data2 = self.titanic_data[
          ["Survived", "Sex", "Pclass"]
      ]
  
imports: import unittest
  import pandas
  from pgmpy.estimators import AICScore, BDeuScore, BDsScore, BicScore, K2Score
  from pgmpy.models import BayesianNetwork
label_desc: Use image node_id 1 for calling the TestK2Score obj's underlying member method code with example usage: obj.setUp() without return types