Time_sig.S.Period

`sig
type +'a period constraint 'a = [< Period.date_field ]
type t = Period.date_field period
val empty : [< Period.date_field ] period
val add : ([< Period.date_field ] as 'a) period -> 'a period -> 'a period
val sub : ([< Period.date_field ] as 'a) period -> 'a period -> 'a period
val opp : ([< Period.date_field ] as 'a) period -> 'a period
val equal :
[< Period.date_field ] period -> [< Period.date_field ] period -> bool
val compare :
[< Period.date_field ] period -> [< Period.date_field ] period -> int
val hash : [< Period.date_field ] period -> int
val length : [< Period.date_field ] period -> Time_sig.S.second
val mul : ([< Period.date_field ] as 'a) period -> 'a period -> 'a period
val div : ([< Period.date_field ] as 'a) period -> 'a period -> 'a period
val make : int -> int -> Time_sig.S.second -> [< Period.date_field ] period
val lmake :
?hour:int ->
?minute:int ->
?second:Time_sig.S.second -> unit -> [< Period.date_field ] period
val hour : int -> [< Period.date_field ] period
val minute : int -> [< Period.date_field ] period
val second : Time_sig.S.second -> [< Period.date_field ] period
val to_seconds : [< Period.date_field ] period -> Time_sig.S.second
val to_minutes : [< Period.date_field ] period -> float
val to_hours : [< Period.date_field ] period -> float
end`