How to extract generic parameter type from runtime class definition. (F#)

Program.fs

open System
open System.Collections.Generic

let iedt = typedefof<IEnumerable<int>>
let traverseInterfaceType (targetType: Type) =
    targetType.GetInterfaces()
    |> Seq.filter (fun t -> t.IsGenericType && (t.GetGenericTypeDefinition() = iedt))
    |> Seq.map (fun t -> t.GetGenericArguments().[0])

[<EntryPoint>]
let main argv = 

    let targetType = typeof<List<DateTime>>

    let results = traverseInterfaceType targetType |> Seq.toArray

    printfn "%A" results
    0 // return an integer exit code