how to insert multiple row one time with one transaction realm react native

//start transaction
addContactToCustomer = (id, data) => {

let customerContact = realm.objects('Customer').filtered('_id=$0', id)[0].Contacts;

realm.write(() => {
    customerContact.push(data)
})

        let Book = realm.objects('Book').filtered('_id=$0', id)[0].Contacts;
    
        realm.write(() => {
            Book.push(data)
        })
    
    }

}
//end transaction