# File lib/active_merchant/billing/integrations/e_payment_plans.rb, line 14
        def self.service_url
          mode = ActiveMerchant::Billing::Base.integration_mode
          case mode
          when :production
            "#{production_url}/order/purchase"
          when :test
            "#{test_url}/order/purchase"
          else
            raise StandardError, "Integration mode set to an invalid value: #{mode}"
          end
        end