def process_request(self, server_state):
        """Server-side function to process the request.

        Must be inherited by subclasses.

        Parameters
        ----------
        server_state : ServerState
            Server state data.

        Returns
        -------
        Response
            Response of this request or None if no response.
        """
Server-side function to process the request.

        Must be inherited by subclasses.

        Parameters
        ----------
        server_state : ServerState
            Server state data.

        Returns
        -------
        Response
            Response of this request or None if no response.
        
python/dgl/distributed/rpc.py