code: def download_workers(self):
          
          # Profiling download on different servers showed half the number of CPUs to be optimum for speed.
          default_workers = int(math.ceil(default_num_workers() / 2))
          return self.values.get(Config.DOWNLOAD_WORKERS, default_workers)
docs: Return the number of parallel works to use when downloading a file.
          :return: int number of workers. Specify None or 1 to disable parallel downloading