module ResponseContract =
    let handleNullString (s : string) =
        match s with
        | null -> "null"
        | "" -> "null"
        | _ -> s
        
    type Phone = {
        phone_type : string
        phone_number : string 
    } with
        static member Zero = {
            phone_type = "null"
            phone_number = "null"
        }
    type Email = {
         email_type : string
         address : string 
    } with
        static member Create t a = {
            email_type = handleNullString t
            address = handleNullString a 
        }
        static member Zero = {
            email_type = "null"
            address = "null"
        }