restore_storable (XmlSimple::Cache)

    # File lib/active_support/vendor/xml-simple-1.0.11/xmlsimple.rb, line 41
        def restore_storable(filename)
          cache_file = get_cache_filename(filename)
          return nil unless File::exist?(cache_file)
          return nil unless File::mtime(cache_file).to_i > File::mtime(filename).to_i
          data = nil
          File.open(cache_file) { |f| data = Marshal.load(f) }
          data
        end