Monad.Identityinclude S2 with type ('a, _) t := 'a tval return : 'a -> 'a treturn v returns the (trivial) computation that returns v.
Like all, but ensures that every monadic value in the list produces a unit value, all of which are discarded rather than being collected into a list.
module Syntax : sig ... endAs described at https://ocaml.org/manual/latest/bindingops.html