# File lib/active_merchant/billing/gateways/barclays_epdq.rb, line 219
        def add_order_form(order_id=nil, group_id=nil, &block)
          xml.OrderFormDoc do
            xml.Mode 'P'
            xml.Id(order_id) if order_id
            xml.GroupId(group_id) if group_id
            instance_eval(&block)
          end
        end