I've got a script that converts video files. -l is the short flag for "auto-detect letterboxing and remove if present." I would like to have a corresponding "-nl" flag for "do NOT check for letterboxing." But, what I'm reporting here is that it seems I cannot do "script --no-letterbox filename.mpeg anotherfile.mpeg --letterbox filewithletterboxing.mpeg" because that throws an "unsupported multiple argument type 'TrueClass'" error.