knex transaction update with two tables

I have two table dues and souvenirs haveing a similar column std_id. I want to update both of them using transaction but my code returns 1.

 db.transaction((trx) => {
    return db("dues")
      .where({ std_id: stdid })
      .update({
        level_100: level100,
        level_200: level200,
        level_300: level300,
        level_400: level400,
      })

      .then(() => {
        return db("souvenirs")
          .where({
            std_id: stdid,
          })
          .update({
            t_shirt: tshirt,
            books: books,
          });
      })
      .then((row) => console.log(row))
      .then(trx.commit)
      .catch((err) => console.log(err));
  });