_set_default_values

# File lib/rss/maker/base.rb, line 356
      def _set_default_values(&block)
        keep = {
          :date => date,
          :dc_dates => dc_dates.to_a.dup,
        }
        _date = _parse_date_if_needed(date)
        if _date and !dc_dates.any? {|dc_date| dc_date.value == _date}
          dc_date = self.class::DublinCoreDates::DublinCoreDate.new(self)
          dc_date.value = _date.dup
          dc_dates.unshift(dc_date)
        end
        self.date ||= self.dc_date
        super(&block)
      ensure
        date = keep[:date]
        dc_dates.replace(keep[:dc_dates])
      end