module MoreLabels:sig..end
Extra labeled libraries.
This meta-module provides labelized versions of the Hashtbl, Map and
   Set modules.
This module is intended to be used through open MoreLabels which replaces
   Hashtbl, Map, and Set with their labeled counterparts.
For example:
     open MoreLabels
     Hashtbl.iter ~f:(fun ~key ~data -> g key data) table
   module Hashtbl:sig..end
module Map:sig..end
module Set:sig..end