# File raggle, line 4955
    def Engine::purge_feed_cache
      urls = {}
      $config['feeds'].each { |feed| urls[feed['url']] = true }
      PStore::new($config['feed_cache_path']) { |cache|
        cache.roots.each { |root| 
          unless urls[root]
            $stderr.puts "Purging \"#{root}\"" if $config['verbose']
            cache[root] = nil
          end
        }
      }
    end