# File lib/active_merchant/billing/gateways/braintree_blue.rb, line 50
      def refund(*args)
        # legacy signature: #refund(transaction_id, options = {})
        # new signature: #refund(money, transaction_id, options = {})
        money, transaction_id, options = extract_refund_args(args)
        money = amount(money).to_s if money

        commit do
          result = Braintree::Transaction.refund(transaction_id, money)
          Response.new(result.success?, message_from_result(result),
            {:braintree_transaction => (transaction_hash(result.transaction) if result.success?)},
            {:authorization => (result.transaction.id if result.success?)}
           )
        end
      end