Why does kickstart %post script calling yum api to update spams logs with package download messages?

Issue

• During the %post segment of Kickstart, there is a python scripting used to update the system through the yum api.
• The working piece:

yb = yum.YumBase()
yb.setCacheDir()
yb.preconf.errorlevel = 0
yb.preconf.errorlevel = 0
yb.conf.assumeyes = True
yb.doLock()
yb.update()
yb.resolveDeps()
yb.buildTransaction()
yb.processTransaction()
yb.doUnlock()

• This works however it spams the ks-post.log.2 with tens of thousands of lines like the following:

Updating: libgcc-4.8.5-4.el7.x86_64 0/180604 [1/755]
Updating: libgcc-4.8.5-4.el7.x86_64 65684/180604 [1/755]
Updating: libgcc-4.8.5-4.el7.x86_64 88868/180604 [1/755]
Updating: libgcc-4.8.5-4.el7.x86_64 89028/180604 [1/755]
Updating: libgcc-4.8.5-4.el7.x86_64 89168/180604 [1/755]
Updating: libgcc-4.8.5-4.el7.x86_64 107318/180604 [1/755]
Updating: libgcc-4.8.5-4.el7.x86_64 133912/180604 [1/755]

• How do one tell the api to suppress this output?