receive "message":"Invalid Request."

[17_bzhzq]

            self.websocket = await websockets.connect(self.ws_url)
            async for message in self.websocket:
                print(f'rec message: {message}')

Why do I receive useless messages at intervals?

rec message: {"id":null,"jsonrpc":"2.0","error":{"code":-32600,"message":"Invalid Request."}}

[Aymeric Augustin]

For anyone else who stumbles upon this, presumably the answer is "because the server sent these useless messages".