* This method should return an instance of [ActiveMerchant::Billing::Response](https://github.com/Shopify/active_merchant/blob/master/lib/active_merchant/billing/response.rb#L6)
  * The response instance should be correctly populated with success status or error message, AVS and CVV response and authorization codes where appropriate.
  * Please see other gateways for examples
  * Please look at ActiveMerchant::Billing::Response
* This method should have error handling e.g, rescue from ResponseError