Parameter Make_access.1-T

type ('a, 'b) t
val many : ('at -> ('bt'a'b) Many.t) -> ('a'b) t -> ('at'bt) t

A legal implementation of this function must satisfy the following properties:

many Many.Accessed.return = Fn.id
Fn.compose (many f) (many g)
= many (fun at -> Many.Accessed.bind (f at) ~f:g)