code: def test_get_all_variables(self):
      self.assertEqual(
          self.Independencies3.get_all_variables(),
          frozenset(("a", "b", "c", "d", "e", "f", "g", "h")),
      )
      self.assertEqual(
          self.Independencies4.get_all_variables(),
          frozenset(("f", "d", "e", "c", "h", "g", "b", "c", "a")),
      )
      self.assertEqual(
          self.Independencies5.get_all_variables(),
          frozenset(("a", "b", "c", "d", "e", "f", "g")),
      )
  
imports: import unittest
  from pgmpy.independencies import Independencies, IndependenceAssertion
label_desc: Use image node_id 5 for calling the TestIndependencies obj's underlying member method code with example usage: obj.test_get_all_variables() without return types