code: async def disconnect(self, sid, namespace=None):
          
          namespace = namespace or '/'
          if self.manager.is_connected(sid, namespace=namespace):
              self.logger.info('Disconnecting %s [%s]', sid, namespace)
              self.manager.pre_disconnect(sid, namespace=namespace)
              await self._send_packet(sid, packet.Packet(packet.DISCONNECT,
                                                         namespace=namespace))
              await self._trigger_event('disconnect', namespace, sid)
              self.manager.disconnect(sid, namespace=namespace)
docs: Disconnect a client.
  
          :param sid: Session ID of the client.
          :param namespace: The Socket.IO namespace to disconnect. If this
                            argument is omitted the default namespace is used.
  
          Note: this method is a coroutine.