Event Transform in Zenoss 4.2.3

Hi

I tried following in Zenoss 4.2.3 to transform 'process not running' event. I guess events changed in  4.2.3 so its not working.

import re

sum=evt.summary

if (sum.find("Process up:") >= 0):

  sum=re.sub ("Process up:", "Process not running:", sum)

  evt.summary=sum

  evt._action="history"

Can someone please point me to event transform document for 4.2.3/