use v6.d.PREVIEW;

role Ultramarine::Model::DB {
    method seen-file(:$path) { ... }
    method remove-unseen-files() { ... }

    method is-up-to-date(:$path,:$mtime --> Bool) { ... }
    method ensure-song(:$path,:$mtime,:%metadata) { ... }
    method ensure-file-absent(:$path) { ... }
}