code: def slaveof(self, host, port=None):
          
          if host is None and port is None:
              return self.execute(b'SLAVEOF', b'NO', b'ONE')
          return self.execute(b'SLAVEOF', host, port)
docs: Make the server a slave of another instance,
          or promote it as master.
  
          Calling ``slaveof(None)`` will send ``SLAVEOF NO ONE``.
  
          .. versionchanged:: v0.2.6
             ``slaveof()`` form deprecated
             in favour of explicit ``slaveof(None)``.