Re-calulation produces the same result every day?

[AndKe]

my application call this funtion every day at 00:01 to update the dusk-dawn data:

def init_light_schedule():
    city = LocationInfo("Tromsø", "Norway", "Europe/Tromsø", 69.66, 18.82)
    s = sun(city.observer)  # , s=datetime.date(2021, 2, 18))

    dawn = (s['dawn'] + datetime.timedelta(hours=1))  # negative hours gives earlier "off"
    dusk = (s['dusk'] + datetime.timedelta(hours=1))  # positive hours postpone "on"
    dawn = dawn.replace(tzinfo=None)  # remove timezone info
    dusk = dusk.replace(tzinfo=None)
    now = datetime.datetime.now()
    # for testing now = datetime.datetime(2021, 2, 17, 2, 00)
    print(time.strftime('%H:%M:%S'), ', light schedule updated')
    print('dawn: ', dawn)
    print('dusk: ', dusk)

but the output does not show new data, it is displaying the data of the first day of the script run:
21:37:08 , light schedule updated <<<<< initial run (manual start)
dawn: 2021-03-01 06:08:20.148169
dusk: 2021-03-01 17:47:39.511878
00:01:00 , light schedule updated <<<< the function was executed on schedule, produced the same time(and date)
dawn: 2021-03-01 06:08:20.148169
dusk: 2021-03-01 17:47:39.511878