code: def testWeakRef(self):
      for obj in self.objects:
          wr = weakref.ref(obj)
          self.assertIs(wr(), obj)
          self.assertIn(wr, weakref.getweakrefs(obj))
          wr = weakref.proxy(obj)
          self.assertIn(wr, weakref.getweakrefs(obj))
  
imports: from mpi4py import MPI
  import mpiunittest
  import ctypes
  import operator
  import weakref
  import sys
label_desc: Use image node_id 8 for calling the TestObjModel obj's underlying member method code with example usage: obj.testWeakRef() without return types