code: def fetch_binary(self, fetch_request):
      
      bootstrap_dir = os.path.realpath(os.path.expanduser(self._bootstrap_dir))
      bootstrapped_binary_path = os.path.join(bootstrap_dir, fetch_request.download_path)
      logger.debug("bootstrapped_binary_path: {}".format(bootstrapped_binary_path))
      file_name = fetch_request.file_name
      urls = fetch_request.urls
  
      if self._ignore_cached_download or not os.path.exists(bootstrapped_binary_path):
        self._do_fetch(bootstrapped_binary_path, file_name, urls)
  
      logger.debug('Selected {binary} binary bootstrapped to: {path}'
                   .format(binary=file_name, path=bootstrapped_binary_path))
      return bootstrapped_binary_path
docs: Fulfill a binary fetch request.