code: def _upload(self, items: Iterable[Tuple[str, str]]) -> None:
          
          for src, key in items:
              logger.info(f'Uploading {src} to {key}')
              mimetype, _ = mimetypes.guess_type(src)
              if mimetype is None:
                  logger.warning(f'Could not guess MIME type for {src}')
                  mimetype = 'application/octet-stream'
  
              logger.debug(f'Deduced MIME type: {mimetype}')
              self._bucket.upload_file(src, key, ExtraArgs={
                      'ContentType': mimetype
                  })
docs: Upload a collection of paths to S3.
  
          :param items: An iterable of pairs containing the local path of the
                        file to upload, and the remote path to upload it to. The
                        prefix will be appended to each remote path.