what does sequelize update return code example

Example 1: sequelize update sql

const Tokens = db.define('tokens', {
    token: {
        type: sequelize.STRING
    }
});
// Update tokens table where id
Tokens.update(
          { token: 'new token' },
          { where: {id: idVar} }
     ).then(tokens => {
          console.log(tokens);
     }).catch(err => console.log('error: ' + err));

Example 2: sequelize update

var Book = db.define(‘books’, {
 title: {
   type: Sequelize.STRING
 },
 pages: {
   type: Sequelize.INTEGER
 }
})

Book.update(
   {title: req.body.title},
   {where: req.params.bookId}
 )