title: How to ROT13 encode in Python3?
body: <p>The Python 3 documentation has rot13 listed on its <a href="http://docs.python.org/py3k/library/codecs.html" rel="noreferrer">codecs page</a>.</p>
  
  <p>I tried encoding a string using rot13 encoding:</p>
  
  <pre><code>import codecs
  s  = "hello"
  os = codecs.encode( s, "rot13" )
  print(os)
  </code></pre>
  
  <p>This gives a <code>unknown encoding: rot13</code> error. Is there a different way to use the in-built rot13 encoding? If this encoding has been removed in Python 3 (as Google search results seem to indicate), why is it still listed in Python3 documentation?</p>