Repository: yt-dlp/yt-dlp
File: yt_dlp/extractor/bbc.py (Python)

Code before:
            if not isinstance(captions, xml.etree.ElementTree.Element):
                continue
            subtitles['en'] = [
                {
                    'url': connection.get('href'),
                    'ext': 'ttml',
                },
            ]
            break
        return subtitles

    def _raise_extractor_error(self, media_selection_error):
        raise ExtractorError(
            '%s returned error: %s' % (self.IE_NAME, media_selection_error.id),
            expected=True)

    def _download_media_selector(self, programme_id):
        last_exception = None
        formats, subtitles = [], {}
        for media_set in self._MEDIA_SETS:
            try:
                fmts, sttls = self._download_media_selector_url(
                    self._MEDIA_SELECTOR_URL_TEMPL % (media_set, programme_id), programme_id)
                formats.extend(fmts)
                if sttls:
                    subtitles = self._merge_subtitles(subtitles, sttls)
            except BBCCoUkIE.MediaSelectionError as e:
                if e.id in ('notukerror', 'geolocation', 'selectionunavailable'):
                    last_exception = e
                    continue
                self._raise_extractor_error(e)
        if last_exception:
            if formats or subtitles:
                self.report_warning(
                    '%s returned error: %s' % (self.IE_NAME, last_exception.id))
            else:
                self._raise_extractor_error(last_exception)
        return formats, subtitles

    def _download_media_selector_url(self, url, programme_id=None):
        media_selection = self._download_json(
            url, programme_id, 'Downloading media selection JSON',
            expected_status=(403, 404))
        return self._process_media_selector(media_selection, programme_id)

    def _process_media_selector(self, media_selection, programme_id):
        formats = []
        subtitles = None
        urls = []

        for media in self._extract_medias(media_selection):

Review comment (suggestion):
```suggestion
                self._merge_subtitles(subs, target=subtitles)
```

Code after:
            if not isinstance(captions, xml.etree.ElementTree.Element):
                continue
            subtitles['en'] = [
                {
                    'url': connection.get('href'),
                    'ext': 'ttml',
                },
            ]
            break
        return subtitles

    def _raise_extractor_error(self, media_selection_error):
        raise ExtractorError(
            '%s returned error: %s' % (self.IE_NAME, media_selection_error.id),
            expected=True)

    def _download_media_selector(self, programme_id):
        last_exception = None
        formats, subtitles = [], {}
        for media_set in self._MEDIA_SETS:
            try:
                fmts, subs = self._download_media_selector_url(
                    self._MEDIA_SELECTOR_URL_TEMPL % (media_set, programme_id), programme_id)
                formats.extend(fmts)
                if subs:
                    self._merge_subtitles(subs, target=subtitles)
            except BBCCoUkIE.MediaSelectionError as e:
                if e.id in ('notukerror', 'geolocation', 'selectionunavailable'):
                    last_exception = e
                    continue
                self._raise_extractor_error(e)
        if last_exception:
            if formats or subtitles:
                self.report_warning(f'{self.IE_NAME} returned error: {last_exception.id}')
            else:
                self._raise_extractor_error(last_exception)
        return formats, subtitles

    def _download_media_selector_url(self, url, programme_id=None):
        media_selection = self._download_json(
            url, programme_id, 'Downloading media selection JSON',
            expected_status=(403, 404))
        return self._process_media_selector(media_selection, programme_id)

    def _process_media_selector(self, media_selection, programme_id):
        formats = []
        subtitles = None
        urls = []

        for media in self._extract_medias(media_selection):
            kind = media.get('kind')