import dateutil
from dateutil import tz
utc = tz.tzutc()
t = dateutil.parser.parse("2017-02-24T19:36:20-05:00")
print t
#输出
#datetime.datetime(2017, 2, 24, 19, 36, 20, tzinfo=tzoffset(None, -18000))
t.astimezone(utc)
#输出
#datetime.datetime(2017, 2, 25, 0, 36, 20, tzinfo=tzutc())