If we get a response, add the node to the routing table.  If
        we get no response, make sure it's removed from the routing table.

def handle_call_response(self, result, node):
        """
        If we get a response, add the node to the routing table.  If
        we get no response, make sure it's removed from the routing table.
        """
        if not result[0]:
            log.warning("no response from %s, removing from router", node)
            self.router.remove_contact(node)
            return result

        log.info("got successful response from %s", node)
        self.welcome_if_new(node)
        return result