new_contents: #!/usr/bin/env python
  # encoding: utf-8
  
  """Show the objects with references to a given object.
  """
  
  import gc
  import pprint
  
  
  class Graph(object):
      def __init__(self, name):
          self.name = name
          self.next = None
  
      def set_next(self, next):
          print 'Linking nodes %s.next = %s' % (self, next)
          self.next = next
  
      def __repr__(self):
          return '%s(%s)' % (self.__class__.__name__, self.name)
  
  
  # Construct a graph cycle
  one = Graph('one')
  two = Graph('two')
  three = Graph('three')
  one.set_next(two)
  two.set_next(three)
  three.set_next(one)
  
  print
  print 'three refers to:'
  for r in gc.get_referents(three):
      pprint.pprint(r)
  
subject: add gc_get_referents