How to use Rat inside Buildbot to send email when switching from failure to success and reverse

I started a discussion about "Rat flag for failure or success" on dev ML: https://s.apache.org/IEL4

Maybe someone has experienced that already or can give me an idea?

Or maybe it would useful to add another Optional Parameters to "apache-rat:check" to allow sending an email on a conditon, like if numUnapprovedLicenses is not 0? Or this could be part of "Apache Rat Ant Task Library", or something else?