Shopify Buy SDK iOS

Within Xcode when initializing the client via code below, do I insert this code in my app declaration Swift file or can it be just another Swift file included in my app? Thanks!


let client = Graph.Client(
  shopDomain: "your-shop-name.myshopify.com",
  apiKey: "your-storefront-access-token",
  locale: Locale(identifier: "en_US")
)