code: def package_roles(request, package_name):
      
      session = DBSession()
      package = Package.by_name(session, package_name)
      owners = [('Owner', o.name) for o in package.owners]
      maintainers = [('Maintainer', o.name) for o in package.maintainers]
      return owners + maintainers
docs: Retrieve a list of users and their attributes roles for a given
      package_name. Role is either 'Maintainer' or 'Owner'.