[Zope-dev] Module changes not taking in external method

Hi I am a zope newbie getting started by using external methods. I am importing modules from another package in my external methods and having some problems. When I change code in the external method, I see thos changes take right away when I call the method from the browser. But when I change code in the imported modules, I don't see the changes take until I reboot zope. Is zope cacheing my modules? Any thoughts? thanks, Ted