code: def get_indicator(self, resource):
          
          path = resource.real_path
          # on dos, mtime does not change for a folder when files are added
          if os.name != 'posix' and os.path.isdir(path):
              return (os.path.getmtime(path),
                      len(os.listdir(path)),
                      os.path.getsize(path))
          return (os.path.getmtime(path),
                  os.path.getsize(path))
docs: Return the modification time and size of a `Resource`.