code: def test_get_variables(self):
      var_expected = [
          "VisitToAsia",
          "Tuberculosis",
          "Smoking",
          "LungCancer",
          "TbOrCa",
          "XRay",
          "Bronchitis",
          "Dyspnea",
      ]
      self.assertListEqual(self.reader.get_variables(), var_expected)
  
imports: import unittest
  import numpy
  from pgmpy import config
  from pgmpy.readwrite import NETReader, NETWriter
  from pgmpy.utils import compat_fns, get_example_model
label_desc: Use image node_id 2 for calling the TestNETReader obj's underlying member method code with example usage: obj.test_get_variables() without return types