This will get you the arch. information that yum knows about.

{{{
import rpmUtils.arch

# Directly...
print '$arch =', rpmUtils.arch.getCanonArch()
print '$basearch =', rpmUtils.arch.getBaseArch()

import yum

yb = yum.YumBase()
# Via. yum
print '$arch =', yb.arch.canonarch
print '$basearch =', yb.arch.basearch

}}}