Glassfy.initialize(apiKey:"8NOV6FQBHHRJ4F9N2HV0HUXOQ5LL0QA3")

Glassfy.offerings { (offers, error) in
  guard let offer = offers?["my_offering"],
    let sku = offer.skus.first else { return }

Glassfy.purchase(sku: sku) {(t, error) in
  if let permission = t?.permissions["premium"],
      permission.isValid {
        // unlock premium
      }
  }
}