'Return a string representation of the Job object.
Example result:
<Job(2013-06-14 11:01:36.884000, 20s, <function upper at 0x02386BF0>)>'

def __str__(self):

    iso_time = str(datetime.fromtimestamp(self.next_time))
    return (u'<Job(%s,    %ss,    %s)>' % (iso_time, self.interval, self.func))
