How to ROT13 encode in Python3?

The Python 3 documentation has rot13 listed on its codecs page.

I tried encoding a string using rot13 encoding:

import codecs
 s  = "hello"
 os = codecs.encode( s, "rot13" )
 print(os)
 

This gives a unknown encoding: rot13 error. Is there a different way to use the in-built rot13 encoding? If this has been removed in Python 3, why is it still listed in Python3 documentation?

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