from datetime import datetime,date,timedelta


a=[date.today(), date.today() + timedelta(days=1), date.today() - timedelta(days=1)]
print a # prints '[datetime.date(2013, 1, 22), datetime.date(2013, 1, 23), datetime.date(2013, 1, 21)]'
a = a.sort()
print a # prints 'None'....what???

from datetime import datetime

dateList = ['2018-09-07 19:00:46',
            '2018-09-03 19:39:42',
            '2018-09-04 09:46:42',
            '2018-09-02 14:21:22',
            '2018-09-05 19:19:34',
            '2018-09-03 13:35:17',
            '2018-09-05 08:19:35',
            '2018-09-07 05:22:54',
            '2018-09-07 19:01:02']

sorted([datetime.strptime(dt, "%Y-%m-%d %H:%M:%S") for dt in dateList])

[datetime.datetime(2018, 9, 2, 14, 21, 22),
 datetime.datetime(2018, 9, 3, 13, 35, 17),
 datetime.datetime(2018, 9, 3, 19, 39, 42),
 datetime.datetime(2018, 9, 4, 9, 46, 42),
 datetime.datetime(2018, 9, 5, 8, 19, 35),
 datetime.datetime(2018, 9, 5, 19, 19, 34),
 datetime.datetime(2018, 9, 7, 5, 22, 54),
 datetime.datetime(2018, 9, 7, 19, 0, 46),
 datetime.datetime(2018, 9, 7, 19, 1, 2)]