code: func (ctrl Controller) Checkout(w http.ResponseWriter, req *http.Request) {
  	hasAmazon := req.URL.Query().Get("access_token")
  	order := getCurrentOrderWithItems(w, req)
  	ctrl.View.Execute("checkout", map[string]interface{}{"Order": order, "HasAmazon": hasAmazon}, req, w)
  }
docs: // Checkout checkout shopping cart