[Zope] Quering ZPT macros?

Hi again, Is there anyway to query a ZPT about its macros. I want to implement one macro per meta_type, but I'm not going to implement all meta_types so I would like to query the template if the macro is available. I guess I could use a try-statement to trap any non existing macros, but I would rather query it more explicitly. Best Regards, Johan CArlsson