'Parameters
utc_offset : `~astropy.units.Quantity` (optional)
Offset from UTC in days. Defaults to zero.
dst : `~astropy.units.Quantity` (optional)
Daylight Savings Time offset in days. Defaults to zero
(no daylight savings).
tzname : string, `None` (optional)
Name of timezone
Examples
>>> from datetime import datetime
>>> from astropy.time import TimezoneInfo  # Specifies a timezone
>>> import astropy.units as u
>>> utc = TimezoneInfo()    # Defaults to UTC
>>> utc_plus_one_hour = TimezoneInfo(utc_offset=1*u.hour)  # UTC+1
>>> dt_aware = datetime(2000, 1, 1, 0, 0, 0, tzinfo=utc_plus_one_hour)
>>> print(dt_aware)
2000-01-01 00:00:00+01:00
>>> print(dt_aware.astimezone(utc))
1999-12-31 23:00:00+00:00'

@u.quantity_input(utc_offset=u.day, dst=u.day)
def __init__(self, utc_offset=(0 * u.day), dst=(0 * u.day), tzname=None):

    if ((utc_offset == 0) and (dst == 0) and (tzname is None)):
        tzname = u'UTC'
    self._utcoffset = datetime.timedelta(utc_offset.to_value(u.day))
    self._tzname = tzname
    self._dst = datetime.timedelta(dst.to_value(u.day))
