How to use the saml.Saml11.create function in saml

if(!audience){
      return next(new Error('audience is required'));
    }

    audience = asResource(audience);

    var user = options.getUserFromRequest(req);
    if(!user) return res.send(401);

    var ctx = options.wctx || req.query.wctx;
    if (!options.jwt) {
      var profileMap = options.profileMapper(user);
      var claims = profileMap.getClaims(options);
      var ni = profileMap.getNameIdentifier(options);
      saml11.create({  
        signatureAlgorithm:   options.signatureAlgorithm,
        digestAlgorithm:      options.digestAlgorithm,
        cert:                 options.cert,
        key:                  options.key,
        issuer:               asResource(options.issuer),
        lifetimeInSeconds:    options.lifetime || (60 * 60 * 8),
        audiences:            audience,
        attributes:           claims,
        nameIdentifier:       ni.nameIdentifier,
        nameIdentifierFormat: ni.nameIdentifierFormat,
        encryptionPublicKey:  options.encryptionPublicKey,
        encryptionCert:       options.encryptionCert
      }, function(err, assertion) {
        if (err) return next(err);
        var escapedWctx = utils.escape(utils.escape(ctx)); // we need an escaped value for RequestSecurityTokenResponse.Context
        var escapedAssertion = utils.escape(assertion); // we need an escaped value for RequestSecurityTokenResponse.Context