как сделать ограничение выбора времени в models.DateTimeField
time_choices = (
(time(8, 00, ), '08:00'),
(time(8, 30, ), '08:30'),
(time(9, 00, ), '09:00'),
(time(9, 30, ), '09:30'),
(time(10, 00, ), '10:00'),
(time(10, 30, ), '10:30'),
(time(11, 00, ), '11:00'),
(time(11, 30, ), '11:30'),
(time(12, 00, ), '12:00'),
(time(13, 00, ), '13:00'),
(time(13, 30, ), '13:30'),
(time(14, 00, ), '14:00'),
(time(14, 30, ), '14:30'),
(time(15, 00, ), '15:00'),
(time(15, 30, ), '15:30'),
(time(16, 00, ), '16:00'),
(time(16, 30, ), '16:30'),
(time(17, 00, ), '17:00'),
(time(17, 30, ), '17:30'),
(time(18, 00, ), '18:00'),
(time(18, 30, ), '18:30'),
(time(19, 00, ), '19:00'),
(time(19, 30, ), '19:30'),
)
типа так