_set_default_values

# File lib/rss/maker/base.rb, line 382
      def _set_default_values(&block)
        keep = {
          :dc_languages => dc_languages.to_a.dup,
        }
        _language = language
        if _language and
            !dc_languages.any? {|dc_language| dc_language.value == _language}
          dc_language = self.class::DublinCoreLanguages::DublinCoreLanguage.new(self)
          dc_language.value = _language.dup
          dc_languages.unshift(dc_language)
        end
        super(&block)
      ensure
        dc_languages.replace(keep[:dc_languages])
      end