module Make_lever:
Creates a LEVER module from a function type as specified in
      FUN_TYPE
| Parameters: | 
 | 
type 
argument type
type 
result type
typet =s -> r
val register : Netplex_types.controller ->
       (Netplex_types.controller -> t) -> tlet reg_lever = register ctrl raw_lever:
        Registers raw_lever in the controller ctrl, so one can call
        reg_lever to activate it. For example:
 
           module LT = struct type s = unit type r = int end
           module L = Make_lever(LT)
         
           let get_num_services =
             L.register ctrl (fun ctrl () -> List.length ctrl#services)
        The registration must be done in controller context, e.g.
        in the pre_start_hook of a container.
From the running container, one can now call:
 get_num_services() to get the current length of the ctrl#services list.