How to use the instaloader.instaloader._PostPathFormatter.format function in instaloader

def download_storyitem(self, item: StoryItem, target: Union[str, Path]) -> bool:
        """Download one user story.

        :param item: Story item, as in story['items'] for story in :meth:`get_stories`
        :param target: Replacement for {target} in dirname_pattern and filename_pattern
        :return: True if something was downloaded, False otherwise, i.e. file was already there
        """

        date_local = item.date_local
        dirname = _PostPathFormatter(item).format(self.dirname_pattern, target=target)
        filename = os.path.join(dirname, self.format_filename(item, target=target))
        os.makedirs(os.path.dirname(filename), exist_ok=True)
        downloaded = False
        if not item.is_video or self.download_video_thumbnails is True:
            url = item.url
            downloaded = self.download_pic(filename=filename, url=url, mtime=date_local)
        if item.is_video and self.download_videos is True:
            downloaded |= self.download_pic(filename=filename, url=item.video_url, mtime=date_local)
        # Save caption if desired
        metadata_string = _ArbitraryItemFormatter(item).format(self.storyitem_metadata_txt_pattern).strip()
        if metadata_string:
            self.save_caption(filename=filename, mtime=item.date_local, caption=metadata_string)
        # Save metadata as JSON if desired.
        if self.save_metadata is not False:
            self.save_metadata_json(filename, item)
        self.context.log()

def format_filename(self, item: Union[Post, StoryItem], target: Optional[Union[str, Path]] = None):
        """Format filename of a :class:`Post` or :class:`StoryItem` according to ``filename-pattern`` parameter.

        .. versionadded:: 4.1"""
        return _PostPathFormatter(item).format(self.filename_pattern, target=target)

def download_post(self, post: Post, target: Union[str, Path]) -> bool:
        """
        Download everything associated with one instagram post node, i.e. picture, caption and video.

        :param post: Post to download.
        :param target: Target name, i.e. profile name, #hashtag, :feed; for filename.
        :return: True if something was downloaded, False otherwise, i.e. file was already there
        """

        dirname = _PostPathFormatter(post).format(self.dirname_pattern, target=target)
        filename = os.path.join(dirname, self.format_filename(post, target=target))
        os.makedirs(os.path.dirname(filename), exist_ok=True)

        # Download the image(s) / video thumbnail and videos within sidecars if desired
        downloaded = True
        self._committed = self.check_if_committed(filename)
        if self.download_pictures:
            if post.typename == 'GraphSidecar':
                edge_number = 1
                for sidecar_node in post.get_sidecar_nodes():
                    # Download picture or video thumbnail
                    if not sidecar_node.is_video or self.download_video_thumbnails is True:
                        downloaded &= self.download_pic(filename=filename, url=sidecar_node.display_url,
                                                        mtime=post.date_local, filename_suffix=str(edge_number))
                    # Additionally download video if available and desired
                    if sidecar_node.is_video and self.download_videos is True: