Add methods to open dialogs and process results

        filename = f"{now}_poolpay.csv"

        self.deliver_text(StringIO(persons_csv), save_filename=filename)

    def _open_person_dialog(self, maybe_person: Person | None) -> None:

        def apply_person_details(result: PersonDialogResult) -> None:

            person = maybe_person or Person()

            db.session.add(person)

            person.name = result.name

            person.cl_account_name = result.cl_account_name

            # Orphaned cards will be deleted, re-creating doesn't matter because

            # they will be identical to the old instances.

            person.cards = [Card(id=card_id) for card_id in result.card_ids]

            db.session.commit()

            self.action_reload()

        self.push_screen(

            PersonDialog(maybe_person),

            callback=apply_person_details

        )

    def _open_balance_dialog(self, person: Person) -> None:

        def apply_balance_change(result: BalanceDialogResult) -> None:

            person.balance_cents = result.new_balance_cents

            db.session.commit()

            self.action_reload()

        self.push_screen(

            BalanceDialog(person),

            callback=apply_balance_change,

        )

    def _open_delete_dialog(self, person: Person) -> None:

        def apply_delete() -> None:

            db.session.delete(person)

            db.session.commit()

            self.action_reload()

        self.push_screen(

            DeletePersonDialog(person),

            callback=apply_delete,

        )