code: def postOptions(self):
          
          o = self.store.findFirst(
              offering.InstalledOffering,
              (offering.InstalledOffering.offeringName ==
               self["name"]))
          if o is None:
              raise usage.UsageError("No offering of that name"
                                     " is installed.")
          fp = self.store.findUnique(publicweb.FrontPage)
          fp.defaultApplication = o.application
docs: Find an installed offering and set the site front page to its
          application's front page.