How to use the txaio.reject function in txaio

def on_error(err):
            """
            this may seem redundant after looking at _connect_transport, but
            it will handle a case where something goes wrong in
            _connect_transport itself -- as the only connect our
            caller has is the 'done' future
            """
            transport.connect_failures += 1
            # something bad has happened, and maybe didn't get caught
            # upstream yet
            if not txaio.is_called(done):
                txaio.reject(done, err)
        txaio.add_callbacks(d, None, on_error)

def lost(fail):
                rtn = orig(fail)
                if not txaio.is_called(done):
                    # asyncio will call connection_lost(None) in case of
                    # a transport failure, in which case we create an
                    # appropriate exception
                    if fail is None:
                        fail = TransportLost("failed to complete connection")
                    txaio.reject(done, fail)
                return rtn
            proto.connection_lost = lost

requests.clear()

        if outstanding:
            self.log.info(
                'Cancelling {count} outstanding requests',
                count=len(outstanding),
            )
        for request in outstanding:
            self.log.debug(
                'cleaning up outstanding {request_type} request {request_id}, '
                'firing errback on user handler {request_on_reply}',
                request_on_reply=request.on_reply,
                request_id=request.request_id,
                request_type=request.__class__.__name__,
            )
            txaio.reject(request.on_reply, exc)
            # wait for any async-ness in the error handlers for on_reply
            txaio.add_callbacks(d, lambda _: request.on_reply, lambda _: request.on_reply)
        return d

on_reply = self._subscribe_reqs.pop(msg.request).on_reply

                # ERROR reply to UNSUBSCRIBE
                elif msg.request_type == message.Unsubscribe.MESSAGE_TYPE and msg.request in self._unsubscribe_reqs:
                    on_reply = self._unsubscribe_reqs.pop(msg.request).on_reply

                # ERROR reply to REGISTER
                elif msg.request_type == message.Register.MESSAGE_TYPE and msg.request in self._register_reqs:
                    on_reply = self._register_reqs.pop(msg.request).on_reply

                # ERROR reply to UNREGISTER
                elif msg.request_type == message.Unregister.MESSAGE_TYPE and msg.request in self._unregister_reqs:
                    on_reply = self._unregister_reqs.pop(msg.request).on_reply

                if on_reply:
                    txaio.reject(on_reply, self._exception_from_message(msg))
                else:
                    raise ProtocolError("WampAppSession.onMessage(): ERROR received for non-pending request_type {0} and request ID {1}".format(msg.request_type, msg.request))

            else:

                raise ProtocolError("Unexpected message {0}".format(msg.__class__))

on_reply = self._subscribe_reqs.pop(msg.request).on_reply

                # ERROR reply to UNSUBSCRIBE
                elif msg.request_type == message.Unsubscribe.MESSAGE_TYPE and msg.request in self._unsubscribe_reqs:
                    on_reply = self._unsubscribe_reqs.pop(msg.request).on_reply

                # ERROR reply to REGISTER
                elif msg.request_type == message.Register.MESSAGE_TYPE and msg.request in self._register_reqs:
                    on_reply = self._register_reqs.pop(msg.request).on_reply

                # ERROR reply to UNREGISTER
                elif msg.request_type == message.Unregister.MESSAGE_TYPE and msg.request in self._unregister_reqs:
                    on_reply = self._unregister_reqs.pop(msg.request).on_reply

                if on_reply:
                    txaio.reject(on_reply, self._exception_from_message(msg))
                else:
                    raise ProtocolError("WampAppSession.onMessage(): ERROR received for non-pending request_type {0} and request ID {1}".format(msg.request_type, msg.request))

            else:

                raise ProtocolError("Unexpected message {0}".format(msg.__class__))

def on_disconnect(session, was_clean):
                    self.log.debug(
                        "session on_disconnect: was_clean={was_clean}",
                        was_clean=was_clean,
                    )
                    if not txaio.is_called(done):
                        if was_clean:
                            # eg the session has left the realm, and the transport was properly
                            # shut down. successfully finish the connection
                            txaio.resolve(done, None)
                        else:
                            txaio.reject(done, RuntimeError('transport closed uncleanly'))
                session.on('disconnect', on_disconnect)

def error(fail):
            self._delay_f = None
            if self._stopping:
                # might be better to add framework-specific checks in
                # subclasses to see if this is CancelledError (for
                # Twisted) and whatever asyncio does .. but tracking
                # if we're in the shutdown path is fine too
                txaio.resolve(self._done_f, None)
            else:
                self.log.info("Internal error {msg}", msg=txaio.failure_message(fail))
                self.log.debug("{tb}", tb=txaio.failure_format_traceback(fail))
                txaio.reject(self._done_f, fail)

def on_connect_success(result):
            # async connect call returns a 2-tuple
            transport, proto = result

            # in the case where we .abort() the transport / connection
            # during setup, we still get on_connect_success but our
            # transport is already closed (this will happen if
            # e.g. there's an "open handshake timeout") -- I don't
            # know if there's a "better" way to detect this? #python
            # doesn't know of one, anyway
            if transport.is_closing():
                if not txaio.is_called(done):
                    reason = getattr(proto, "_onclose_reason", "Connection already closed")
                    txaio.reject(done, TransportLost(reason))
                return

            # if e.g. an SSL handshake fails, we will have
            # successfully connected (i.e. get here) but need to
            # 'listen' for the "connection_lost" from the underlying
            # protocol in case of handshake failure .. so we wrap
            # it. Also, we don't increment transport.success_count
            # here on purpose (because we might not succeed).

            # XXX double-check that asyncio behavior on TLS handshake
            # failures is in fact as described above
            orig = proto.connection_lost

            @wraps(orig)
            def lost(fail):
                rtn = orig(fail)

self.onUserError(txaio.create_failure(), "While firing on_progress")
                                    except:
                                        pass

                    else:
                        # process final call result

                        # drop original request
                        del self._call_reqs[msg.request]

                        # user callback that gets fired
                        on_reply = call_request.on_reply

                        # above might already have rejected, so we guard ..
                        if enc_err:
                            txaio.reject(on_reply, enc_err)
                        else:
                            if msg.kwargs:
                                if msg.args:
                                    res = types.CallResult(*msg.args, **msg.kwargs)
                                else:
                                    res = types.CallResult(**msg.kwargs)
                                txaio.resolve(on_reply, res)
                            else:
                                if msg.args:
                                    if len(msg.args) > 1:
                                        res = types.CallResult(*msg.args)
                                        txaio.resolve(on_reply, res)
                                    else:
                                        txaio.resolve(on_reply, msg.args[0])
                                else:
                                    txaio.resolve(on_reply, None)