If someone's fixing the syntax errors, note there's also https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1981103 which (in the initial comment) mentions another problem and its fix.
If someone's fixing the syntax errors, note there's also https:/ /bugs.launchpad .net/ubuntu/ +source/ ifupdown/ +bug/1981103 which (in the initial comment) mentions another problem and its fix.