public HttpResponseMessage GetProductById(Guid? id)
 {
     try
     {
         var productsService = new ProductsService();
         var product = productsService.GetProductById(id);
         var response = Request.CreateResponse(HttpStatusCode.OK, product);
         return response;
     }
     catch (Exception e)
     {
         var error = Request.CreateResponse(HttpStatusCode.InternalServerError, e.Message);
         return error;
     }
 }
 public HttpResponseMessage AddNewProduct(PRODUCT product)
 {
     try
     {
         var productsService = new ProductsService();
         var id = productsService.AddNewProduct(product);
         var response = Request.CreateResponse(HttpStatusCode.OK, id);
         return response;
     }
     catch (Exception e)
     {
         var error = Request.CreateResponse(HttpStatusCode.InternalServerError, e.Message);
         return error;
     }
 }