    open Graphics
    open Types
    (* #load "graphics.cma" *)
    (* #load "fixed.cmo" *)

    let _ = open_graph " 1024x768"
    let _ = set_color black

    let plot_car =
      let size_y = size_y () in
      fun ({x=x; y=y},_,_) ->
        Graphics.plot (Fixed.to_coord x) (size_y - Fixed.to_coord y)

    let plot freq cars =
      ignore
      (List.fold_left (fun counter car -> if counter <= 0
    		   then (plot_car car; freq)
    		   else pred counter) freq cars)

    let list_iteri f l =
      ignore (List.fold_left (fun i elt -> f i elt; i+1) 0 l)

    let array_for_all f a =
      let length = Array.length a in
      let rec loop i =
        if i = length then true else f a.(i) && loop (i+1) in
        loop 0

    let rec dedoublonne = function
      |a::b::q -> if a = b then dedoublonne (b::q) else a :: dedoublonne (b::q)
      |[a] -> [a]
      |[] -> []

    let merge_songs db = function
      | [] | [_] -> ()
      | id :: id's ->
        let mysql_ids = List.map ml642int id's in
        ()