code: def testWeakRefs(self):
      # verify weak references
      p = proxy(self.f)
      p.write(b"teststring")
      self.assertEqual(self.f.tell(), p.tell())
      self.f.close()
      self.f = None
      gc_collect()  # For PyPy or other GCs.
      self.assertRaises(ReferenceError, getattr, p, "tell")
  
imports: import sys
  import os
  import unittest
  from array import array
  from weakref import proxy
  import io
  import _pyio
  from test.support import gc_collect
  from test.support.os_helper import TESTFN
  from test.support import os_helper
  from test.support import warnings_helper
  from collections import UserList
label_desc: Use image node_id 3 for calling the AutoFileTests obj's underlying member method code with example usage: obj.testWeakRefs() without return types