[Zope] DTML form to modifiy folder properties

Have this DTML form that used to work with 2.6. A folder has a lines property called day1. User enters text in a field and submits. The current value of day1 is read into a variable. The new value is appended and sorted and manageChangeProperties called and all is well. WAS well... now Zope complains that 'tuple has no method append' Did properties change in 2.7 ?? Thanks