time_str = '100:00:00'
hours, minutes, seconds = [int(i) for i in time_str.split(':')]
time_in_seconds = hours * 60 * 60 + minutes * 60 + seconds
time_in_seconds
now = datetime.datetime.now()
now
new_time = now + datetime.timedelta(seconds=time_in_seconds)
new_time
Разобрать строку времени в python