Parameter Make_access.1-T
val optional_getter : ('at -> 'a Base.option) -> ('a, 'b) t -> ('at, 'bt) t
A legal implementation of this function must satisfy the following properties:
optional_getter Option.some = Fn.id
Fn.compose (optional_getter f) (optional_getter g) = optional_getter (fun a -> Option.bind (f a) ~f:g)