validate_duplicate_links

# File lib/rss/atom.rb, line 233
      def validate_duplicate_links(links)
        link_infos = {}
        links.each do |link|
          rel = link.rel || "alternate"
          next unless rel == "alternate"
          key = [link.hreflang, link.type]
          if link_infos.has_key?(key)
            raise TooMuchTagError.new("link", tag_name)
          end
          link_infos[key] = true
        end
      end