    # File lib/action_controller/caching/fragments.rb, line 121
          def expire_fragment(key, options = nil)
            return unless cache_configured?

            key = key.is_a?(Regexp) ? key : fragment_cache_key(key)

            if key.is_a?(Regexp)
              self.class.benchmark "Expired fragments matching: #{key.source}" do
                cache_store.delete_matched(key, options)
              end
            else
              self.class.benchmark "Expired fragment: #{key}" do
                cache_store.delete(key, options)
              end
            end
          end