How to convert ISO 8601 time to UTC in python?

There are many approaches, i'll try to list all of them i can.

1) ts = '2015-06-02T12:14:55-04:00'

print datetime.datetime.strptime(ts[:-6],'%Y-%m-%dT%H:%M:%S')+\
            datetime.timedelta(hours=int(ts[-5:-3]),
            minutes=int(ts[-2:]))*int(ts[-6:-5]+'1')

would print
2015-06-02 08:14:55