# File lib/active_merchant/billing/gateways/sage_pay.rb, line 109
      def refund(money, identification, options = {})
        requires!(options, :order_id, :description)
        
        post = {}
        
        add_credit_reference(post, identification)
        add_amount(post, money, options)
        add_invoice(post, options)
        
        commit(:credit, post)
      end