Implement a C# Interface in F#

IMyInterface.cs

namespace Domain
{
    public interface IMyInterface
    {
        string MyProperty { get; set; }

        void PerformAction();

        decimal MethodWithParameters(decimal a, int b);
    }
}

MyImplementation.fs

namespace Functional

open Domain

module MyModule =

    type MyImplementation() =

        let mutable TheVal = ""

        let DoFunction = 
            printfn "hello"
            ()
        
        let DivideValues a b =
            a / decimal b

        interface IMyInterface with
            member this.MyProperty with get() = TheVal
            member this.MyProperty with set(value:string) = TheVal <- value
            member this.PerformAction() = DoFunction
            member this.MethodWithParameters (a, b) =
                DivideValues (a:decimal) (b:int)