[Zope] Newbie in python script

[CY]

I would like to know how-to extract results variable from a python script.
The python script will extract and parse the string into y, m, d variables.
How do I pass these variables into dtml method?

TQ

Python script
=========
parameter = yearmonthdate

ymd=string.split(yearmonthday,"/")
y=ymd[0]
m=ymd[1]
d=ymd[2]
return y, m, d


DTML method
==========
<dtml-var expr="splitDate('2003/03/11')">