'Returns an :class:`Arrow <arrow.arrow.Arrow>` object, representing "now".
:param tz: (optional) An expression representing a timezone.  Defaults to local time.
Recognized timezone expressions:
- A ``tzinfo`` object.
- A ``str`` describing a timezone, similar to \'US/Pacific\', or \'Europe/Berlin\'.
- A ``str`` in ISO-8601 style, as in \'+07:00\'.
- A ``str``, one of the following:  \'local\', \'utc\', \'UTC\'.
Usage::
>>> import arrow
>>> arrow.now()
<Arrow [2013-05-07T22:19:11.363410-07:00]>
>>> arrow.now(\'US/Pacific\')
<Arrow [2013-05-07T22:19:15.251821-07:00]>
>>> arrow.now(\'+02:00\')
<Arrow [2013-05-08T07:19:25.618646+02:00]>
>>> arrow.now(\'local\')
<Arrow [2013-05-07T22:19:39.130059-07:00]>'

def now(self, tz=None):

    if (tz is None):
        tz = dateutil_tz.tzlocal()
    elif (not isinstance(tz, tzinfo)):
        tz = parser.TzinfoParser.parse(tz)
    return self.type.now(tz)
