Mystical delegate converter in F#

DelegateConverter.fs

open System

type Del = delegate of int -> int

let convert1 (d: Func<int, int>): Del = (# "" d : Del #)
let convert2 (d: Func<int, int>): Del = Del(fun x -> d.Invoke x)

[<EntryPoint>]
let main argv =
    let x = Func<int, int>(fun x -> x)
    let y = convert1 x
    let z = convert2 x
    printfn "%A" (x.GetType()) // System.Func`2[System.Int32,System.Int32]
    printfn "%A" (y.GetType()) // System.Func`2[System.Int32,System.Int32] 
    printfn "%A" (z.GetType()) // Program+Del

    0