code: def download_source_dists(self, arguments, use_wheels=False):
          
          download_timer = Timer()
          logger.info("Downloading missing distribution(s) ..")
          requirements = self.get_pip_requirement_set(arguments, use_remote_index=True, use_wheels=use_wheels)
          logger.info("Finished downloading distribution(s) in %s.", download_timer)
          return requirements
docs: Download missing source distributions.
  
          :param arguments: The command line arguments to ``pip install ...`` (a
                            list of strings).
          :param use_wheels: Whether pip and pip-accel are allowed to use wheels_
                             (:data:`False` by default for backwards compatibility
                             with callers that use pip-accel as a Python API).
          :raises: Any exceptions raised by pip.