@classmethod
def _merge_subtitles(cls, subtitle_dict1, subtitle_dict2):
    ' Merge two subtitle dictionaries, language by language. '
    ret = dict(subtitle_dict1)
    for lang in subtitle_dict2:
        ret[lang] = cls._merge_subtitle_items(subtitle_dict1.get(lang, []), subtitle_dict2[lang])
    return ret
Merge two subtitle dictionaries, language by language.
@classmethod
def _merge_subtitles(cls, subtitle_dict1, subtitle_dict2):
    '  '
    ret = dict(subtitle_dict1)
    for lang in subtitle_dict2:
        ret[lang] = cls._merge_subtitle_items(subtitle_dict1.get(lang, []), subtitle_dict2[lang])
    return ret