code: def register_namespace(self, namespace_handler):
          
          if not isinstance(namespace_handler, namespace.Namespace):
              raise ValueError('Not a namespace instance')
          if self.is_asyncio_based() != namespace_handler.is_asyncio_based():
              raise ValueError('Not a valid namespace class for this server')
          namespace_handler._set_server(self)
          self.namespace_handlers[namespace_handler.namespace] = \
              namespace_handler
docs: Register a namespace handler object.
  
          :param namespace_handler: An instance of a :class:`Namespace`
                                    subclass that handles all the event traffic
                                    for a namespace.