# File lib/openid/extensions/pape.rb, line 153
      def get_extension_args
        ns_args = {}
        if @auth_policies.empty?
          ns_args['auth_policies'] = 'none'
        else
          ns_args['auth_policies'] = @auth_policies.join(' ')
        end
        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_time
          unless @auth_time =~ TIME_VALIDATOR
            raise ArgumentError, "auth_time must be in RFC3339 format"
          end
          ns_args['auth_time'] = @auth_time
        end
        return ns_args
      end