checkout_controller.ex

defmodule MangoWeb.CheckoutController do
  use MangoWeb, :controller
  alias Mango.Sales

  def edit(conn, _params) do
    order = conn.assigns.cart
    order_changeset = Sales.change_cart(order)
    render conn, "edit.html",
           order: order,
           order_changeset: order_changeset
  end
end

Hello, Listing 16 in the Checkout chapter says order_changeset = Sales.change_order(order) for what is on line 7.

@thebrianemory, the issue has been corrected.