CartController.cs

public class CartController : ApiController
{
    private readonly ICartService _cartService;

    public CartController(ICartService cartService)
    {
        _cartService = cartService;
    }
    
    [HttpPost]
    public Response<CheckOutResultDto> Checkout(Guid customerId)
    {
        Response<CheckOutResultDto> response = new Response<CheckOutResultDto>();
        try
        {
            response.Object = _cartService.CheckOut(customerId);
        }
        catch (Exception ex)
        {
            //...
        }
        return response;
    }

}