def opt.period
import bend-kit-migrate@0.3.0.0/migrate.bend as Migrateimport Base
508# An absent v2 period is monthly.
509def opt.period(m: Maybe<&1, Scalar>) -> Result<&1, &1, Error, Period>:
510 match m:
511 case None{}:
512 Done{Monthly{}}
513 case Some{SStr{b}}:
514 name.period(Tag.of(b))
515 case Some{s}:
516 Fail{BadField{KPeriod{}}}