>>> import datetime as dt
>>> from tzinfo_examples import HOUR, Eastern
>>> u0 = dt.datetime(2016, 3, 13, 5, tzinfo=dt.timezone.utc)
>>> for i inrange(4):
... u = u0 + i*HOUR
... t = u.astimezone(Eastern)
... print(u.time(), 'UTC =', t.time(), t.tzname())
...
05:00:00 UTC = 00:00:00 EST
06:00:00 UTC = 01:00:00 EST
07:00:00 UTC = 03:00:00 EDT
08:00:00 UTC = 04:00:00 EDT