Conversion functions to translate to and from Schedule_v4_deprecated.t
. Schedules
containing Zoned_between
cannot be downgraded, but all V4 schedules are
expressable as V5 schedules.
module V4 = Schedule_v4_deprecated
val to_v4 : (zoned, 'b) t ‑> (V4.zoned, 'b) V4.t Core__.Import.Or_error.t