[Zope] DTML Method - delete files

I am almost done writing the script but I need to figure out how to compare two dates. For instance, I have this: <dtml-var ZopeTime fmt="%m/%d/%Y"> <dtml-var modification_date fmt="%m/%d/%Y"> *** Now I need to compare the two dates to see if the ZopeTime is greater by 5 days. Any ideas on how to do that using dtml?