[Zope] Checking for nulls in a date/time field

Hi, I thought I saw this before but I am having difficulty in findin gthis answer. I use MS Access and can save the dates in their date/time format. But if the field is empty (close_date) and I populated with a Null, how do I find it? I used this- <dtml-if expr="verify_close_date=='Null'"> and I tried this <dtml-if expr="verify_close_date==' ' ">. I'm just looking for a pointer, thanks. Larry McDonnell Proton Energy Systems 10 Technology Drive Wallingford, CT 06492 (203) 678-2181 Email:lmcdonnell@protonenergy.com www.protonenergy.com