code: def testWeakReferences(self):
      # Calling registerResult on a result should not keep it alive
      result = unittest.TestResult()
      unittest.registerResult(result)
  
      ref = weakref.ref(result)
      del result
  
      # For non-reference counting implementations
      gc.collect()
      gc.collect()
      self.assertIsNone(ref())
  
imports: import gc
  import os
  import sys
  import signal
  import weakref
  from cStringIO import StringIO
  import unittest
label_desc: Use image node_id 10 for calling the TestBreak obj's underlying member method code with example usage: obj.testWeakReferences() without return types