code: def test_cycle(self):
      class myobj:
          pass
  
      o = myobj()
      o.s = slice(o)
      w = weakref.ref(o)
      o = None
      support.gc_collect()
      self.assertIsNone(w())
  
imports: import itertools
  import operator
  import sys
  import unittest
  import weakref
  import copy
  from pickle import loads, dumps
  from test import support
label_desc: Use image node_id 12 for calling the SliceTest obj's underlying member method code with example usage: obj.test_cycle() without return types