def test_multiple(self):
        """
        Test instances from multiple singleton classes.

        @raise AssertionError: If the test fails.
        """
        dummy_class_one_instance_one = self.dummy_class_one()
        dummy_class_one_instance_two = self.dummy_class_one()

        dummy_class_two_instance_one = self.dummy_class_two()
        dummy_class_two_instance_two = self.dummy_class_two()

        self.assertEquals(id(dummy_class_one_instance_one), id(dummy_class_one_instance_two))
        self.assertEquals(id(dummy_class_two_instance_one), id(dummy_class_two_instance_two))

        self.assertNotEquals(id(dummy_class_one_instance_one), id(dummy_class_two_instance_one))
        self.assertNotEquals(id(dummy_class_one_instance_two), id(dummy_class_two_instance_two))

        Test instances from multiple singleton classes.

        @raise AssertionError: If the test fails.
        
tests/creational_tests/test_singleton.py