# File lib/openid/extensions/pape.rb, line 161
      def get_extension_args
        ns_args = {'auth_policies' => @auth_policies.join(' ')}
        if @nist_auth_level
          unless (0..4).member? @nist_auth_level
            raise ArgumentError, "nist_auth_level must be an integer 0 through 4, not #{@nist_auth_level.inspect}"
          end
          ns_args['nist_auth_level'] = @nist_auth_level.to_s
        end

        if @auth_age
          if @auth_age < 0
            raise ArgumentError, "auth_age must be a non-negative integer, not #{@auth_age.inspect}"
          end
          ns_args['auth_age'] = @auth_age.to_s
        end
        return ns_args
      end