code: def newest_release(self, product):
          
          releases = yield self.upcoming_releases(product)
          if not releases:
              raise ProductPagesException('no upcoming releases')
          defer.returnValue(releases[0].shortname)
docs: Get the shortname of the newest upcoming release for a product.
  
          :param product: str, eg. "ceph"
          :returns: deferred that when fired returns the shortname of the newest
                    release.