sig
type t
type datum = t
val low_version : Version.t
val prod_version : Version.t
val test_version : Version.t
val lookup_marshal_fun :
Version.t -> (datum marshal_fun, exn) Core.Std.Result.t
val lookup_unmarshal_fun :
Version.t -> (datum unmarshal_fun, exn) Core.Std.Result.t
end