syslog(3) is cited in the code as inspiration and has been the goto definition for logging levels for 40 years across many, many projects. NOTICE is incredibly useful especially to those of us who are sysadmins.

Why would Python not implement the full suite of syslog levels? Admittedly the case for ALERT and EMERGENCY might be a stretch. It at least doesn't hobble those who want to use them. Without proper coverage one has to settle for unnecessary jumbling of Noteworthy items being buried in the torrent of Informational but not really interesting items.

eg. INFO for attempting a connection. NOTICE for temporary service unavailability or handshake timeout, WARNING (maybe ERROR) for retry exhausted depending on what the failure means to the app.

eg. INFO for login attempts. NOTICE for password expiry date approaching, for failed logins (bad username/passwords, locked/expired account), for password change attempts, for temporary Federated Auth connect failure. None of which rise to the level of WARNING.