This would override addrport set by settings.RUNSERVERPLUS_SERVER_ADDRESS_PORT.

And will also set addrport = None if the environment variable RUNSERVERPLUS_SERVER_ADDRESS_PORT is not defined.

If would make more sense to use something like:

        if not addrport:
            addrport = os.environ.get("RUNSERVERPLUS_SERVER_ADDRESS_PORT")
        if not addrport:
            try:
                addrport = settings.RUNSERVERPLUS_SERVER_ADDRESS_PORT
            except AttributeError:
                pass

So the order of defining the host and port to use will be:

1. CLI Arguments
2. Environment variable
3. Settings value
4. defaults (aka ":{DEFAULT_PORT}")