sig
type t =
Nanosecond
| Microsecond
| Millisecond
| Second
| Minute
| Hour
| Day
val compare : Span.Unit_of_time.t -> Span.Unit_of_time.t -> int
val t_of_sexp : Sexplib.Sexp.t -> Span.Unit_of_time.t
val sexp_of_t : Span.Unit_of_time.t -> Sexplib.Sexp.t
end