code: def _handle_caption_upload(
              self,
              *,
              media_ids: List[str],
              captions: Optional[List[str]],
      ) -> None:
          
          if captions is None:
              captions = []
  
          if len(media_ids) > len(captions):
              captions.extend([self.default_caption_message] * (len(media_ids) - len(captions)))
  
          for i, media_id in enumerate(media_ids):
              caption = captions[i]
              self._upload_caption(media_id=media_id, caption=caption)
docs: Handle uploading all captions.
  
          :param media_ids: media ids of uploads to attach captions to.
          :param captions: captions to be attached to those media ids.
          :returns: None.