// get the Map module
    let map = mapType.Assembly.GetTypes() |> Array.find(fun t -> t.Name = "MapModule")
    // get the MapModule.iter function
    let iter = map.GetMethods(BindingFlags.Static ||| BindingFlags.Public) |> Array.find (fun m -> m.Name = "Iterate")
    // create a unction that we want to pass to Map.iter
    let iterator = (fun k v -> printfn k)
    // get type of iterator function
    let fType = iterator.GetType()
    // tried to build a function type
    let f1Type = FSharpType.MakeFunctionType ( fType, FSharpType.MakeFunctionType(ttt4.GetType(), typeof<unit>  ) )
    // specialise the generic function
    let genericIter = iter.MakeGenericMethod([| fType  ; ttt4.GetType() |])

    //invoke the Map.iter function with our iterator function, and the map instance ttt4
    genericIter.Invoke(null,  [| iterator; ttt4 |]) |> ignore



(*

Unhandled Exception: System.ArgumentException: Object of type 'Program+iterator@288TT[System.Object,System.Object]' cannot be converted to type

'FSharpFunc`2[
         Program+iterator@288TT[System.Object,System.Object],
         FSharpFunc`2[
            FSharpMap`2[
              System.String,
              User+User
            ],
            Unit
          ]
]'.


   at System.RuntimeType.TryChangeType(Object value, Binder binder, CultureInfo culture, Boolean needsSpecialCast)
   at System.Reflection.MethodBase.CheckArguments(Object[] parameters, Binder binder, BindingFlags invokeAttr, CultureInfo culture, Signature sig)
   at System.Reflection.RuntimeMethodInfo.InvokeArgumentsCheck(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)

*)