anchor.diff:    tokenCreate(email: String!, password: String!): CreateToken
     tokenRefresh(token: String!): Refresh
     tokenVerify(token: String!): VerifyToken
  +  checkoutAddPromoCode(checkoutId: ID!, promoCode: String!): CheckoutAddPromoCode
     checkoutBillingAddressUpdate(billingAddress: AddressInput!, checkoutId: ID!): CheckoutBillingAddressUpdate
     checkoutComplete(checkoutId: ID!): CheckoutComplete
     checkoutCreate(input: CheckoutCreateInput!): CheckoutCreate
  
positive.code:   totalPrice: TaxedMoney
  }
  
  type CheckoutBillingAddressUpdate {
    errors: [Error!]
    checkout: Checkout
  
negative.code:   shippingMethodName: String
    token: String!
    voucher: Voucher
    giftCards: [GiftCard]
    discountAmount: Money
    discountName: String!
    translatedDiscountName: String!
  