def by_month(self, chamber, year=None, month=None):
        """
        Return votes for a single month, defaulting to the current month.
        """
        check_chamber(chamber)

        now = datetime.datetime.now()
        year = year or now.year
        month = month or now.month

        path = "{chamber}/votes/{year}/{month}.json".format(
            chamber=chamber, year=year, month=month)
        return self.fetch(path, parse=lambda r: r['results'])
Return votes for a single month, defaulting to the current month.