[MM3-users] Is logging.subscribe working in /etc/mailman.cfg?

I have put the following in /etc/mailman.cfg and restart mailman. An empty file can be created but nothing can be logged when admin or non-member subscribe/unsubscribe. Anything I have missed? So far I can only see log appear in mailman.log and smtp.log. Thanks.

[logging.subscribe] path: subscribe.log level: debug