code: def test_difference_update(self):
      retval = self.s.difference_update(self.items2)
      self.assertEqual(retval, None)
      for c in self.items + self.items2:
          if c in self.items and c not in self.items2:
              self.assertIn(c, self.s)
          else:
              self.assertNotIn(c, self.s)
      self.assertRaises(TypeError, self.s.difference_update, [[]])
      self.assertRaises(
          TypeError, self.s.symmetric_difference_update, [[]]
      )
  
imports: import unittest
  from weakref import WeakSet
  import copy
  import string
  from collections import UserString
  from collections.abc import Set, MutableSet
  import gc
  import contextlib
  from test import support
label_desc: Use image node_id 34 for calling the TestWeakSet obj's underlying member method code with example usage: obj.test_difference_update() without return types