cleanup

# File activesupport/lib/active_support/cache/memory_store.rb, line 40
      def cleanup(options = nil)
        options = merged_options(options)
        instrument(:cleanup, :size => @data.size) do
          keys = synchronize{ @data.keys }
          keys.each do |key|
            entry = @data[key]
            delete_entry(key, options) if entry && entry.expired?
          end
        end
      end