gistfile1.cs

public static Action<IMaybe<TA>> LiftToMaybe<TA>(this Action<TA> func) where  TA : class
{
    return param =>
        {
            var justparam = param as Just<TA>;
            if (justparam == null || justparam.Value == null) return;
            func(justparam.Value);
        };
}