Django How to create a Django Workday hours Field

To create a field storing workday hours it is sometimes good to use secondsto capture and use choices like below.

WORKDAY_CHOICES = (
    (0, '0'),
    (1800, '0.5'),
    (3600, '1'),
    (5400, '1.5'),
    (7200, '2'),
    (9000, '2.5'),
    (10800, '3'),
    (12600, '3.5'),
    (14400, '4'),
    (16200, '4.5'),
    (18000, '5'),
    (19800, '5.5'),
    (21600, '6'),
    (23400, '6.5'),
    (25200, '7'),
    (27000, '7.5'),
    (28800, '8'),
    (30600, '8.5'),
    (32400, '9'),
    (34200, '9.5'),
    (36000, '10')
)

    workday_hours = models.PositiveIntegerField(
        choices=WORKDAY_CHOICES,
        default=28800
    )

But there is a way to do this with a list comprehension

     choices = [(3600 * num, num) for num in range(0, 10, 1)]

Unfortunately range() does not work with a decimal step