you have to re-assign the email attribute of the Person object. Modifying the list in-place has no effect, because the Person object cannot detect changes in that list (it's just a snapshot copy).
Try something like this:import contacts people = contacts.get_all_people() print people.full_name emails = people.email emails.append((u'$!<Other>!$', firstname.lastname@example.org')) people.email = emails # !!! contacts.save()