docs: def _handle_disconnect(self, sid, namespace):
          """Handle a client disconnect."""
          namespace = namespace or '/'
          if namespace == '/':
              namespace_list = list(self.manager.get_namespaces())
          else:
              namespace_list = [namespace]
          for n in namespace_list:
              if n != '/' and self.manager.is_connected(sid, n):
                  self._trigger_event('disconnect', n, sid)
                  self.manager.disconnect(sid, n)
          if namespace == '/' and self.manager.is_connected(sid, namespace):
              self._trigger_event('disconnect', '/', sid)
              self.manager.disconnect(sid, '/')