[CentOS] getfullcomps.py

Just started trying to build Centos 4.x based distros (was doing this
with Centos 3.x before), and I noticed that getfullcomps.py is gone from
the comps-extras package.  Is this no longer necessary?  How does one
automate the building of the comps.xml file now?  Any pointers to new
docs, because the old ones seem to still mention getfullcomps.py?

Thanks...james