Old versions of wire protocol handlers relied on methods
named do_<command> to handle wire protocol commands. The last
definition of these methods on sshserver was removed by
9f6e0e7ef828 ~2 years ago. I think it's time to not support this
mechanism for defining command handlers.

.. api::

sshserver now longers looks for wire protocol command handlers
in methods named do_<command>. Use @wireproto.wireprotocommand
to declare wire protocol command handler functions.