title: how to use 'pickle'
body: <p>my code(i was unable to use 'pickle'):</p>
  
  <pre><code>class A(object):
      def __getstate__(self):
          print 'www'
          return 'sss'
      def __setstate__(self,d):
          print 'aaaa'
  
  import pickle
  a = A()
  s = pickle.dumps(a)
  e = pickle.loads(s)
  print s,e
  </code></pre>
  
  <p>print :</p>
  
  <pre><code>www
  aaaa
  ccopy_reg
  _reconstructor
  p0
  (c__main__
  A
  p1
  c__builtin__
  object
  p2
  Ntp3
  Rp4
  S'sss'
  p5
  b. &lt;__main__.A object at 0x00B08CF0&gt;
  </code></pre>
  
  <p>who can tell me how to use.</p>