code: def each_url
        return enum_for(__method__) unless block_given?
  
        each_link do |link|
          if (url = to_absolute(link))
            yield url
          end
        end
      end
docs: Enumerates over every absolute URL in the page.
  
   @yield [url]
     The given block will be passed every URL in the page.
  
   @yieldparam [URI::HTTP] url
     An absolute URL in the page.
  
   @return [Enumerator]
     If no block is given, an enumerator object will be returned.
  
   @since 0.3.0