I have a session variable called 'undergraduateProjectsDirected' that I declare using the following syntax: <dtml-call "REQUEST.SESSION.set('undergradProjectsDirected', [ ])"> When I try to append items to this list variable, I get the following error: AttributeError: 'NoneType' object has no attribute 'append' I know for a fact that this variable exists since flushing the SESSION attribute of the REQUEST variable using <dtml-var "REQUEST.SESSION"> yields its name and shows that it is initially empty. I am using the following statement to append items: <dtml-call "(REQUEST.SESSION.get('undergraduateProjectsDirected')).append([student_name, description])"> The strange thing is that when I change the name of this variable to 'undergradProjectsDirected', the error does not occur anymore. Has anyone experienced something similar? I think a variable with the same name exists (perhaps I created one in another one of my intranet applications) and Zope is referring to the old copy instead of the newly created one. I tried flushing the transient object container as well but it did not make a difference. Any help would be greatly appreciated. Thank you. - Asad