import datetime
import pytz

def main():
    p = print

    # We'll start by getting the current time.
    now = datetime.datetime.now(pytz.UTC)
    p(now)

    # You can build a datetime object by providing the
    # year, month, day, etc. Times are always associated
    # with a timezone.
    then = datetime.datetime(2009, 11, 17, 20, 34, 58, 651387, pytz.UTC)
    p(then)

    # You can extract the various components of the time
    # value as expected.
    p(then.year)
    p(then.month)
    p(then.day)
    p(then.hour)
    p(then.minute)
    p(then.second)
    p(then.microsecond)
    p(then.tzinfo)

    # The Monday-Sunday weekday is also available.
    p(then.strftime("%A"))

    # These methods compare two times, testing if the
    # first occurs before, after, or at the same time
    # as the second, respectively.
    p(then < now)
    p(then > now)
    p(then == now)

    # The subtraction operation returns a timedelta representing
    # the interval between two times.
    diff = now - then
    p(diff)

    # We can compute the length of the duration in
    # various units.
    p(diff.total_seconds() / 3600)  # hours
    p(diff.total_seconds() / 60)    # minutes
    p(diff.total_seconds())         # seconds
    p(diff.total_seconds() * 1e9)   # nanoseconds

    # You can use addition to advance a time by a given
    # duration, or with a negative value to move backwards by a
    # duration.
    p(then + diff)
    p(then - diff)

if __name__ == "__main__":
    main()