How to use the langcodes.tag_parser.parse_tag function in langcodes

# way that we've already solved.
            tag = tag.to_tag()

        if (tag, normalize) in Language._PARSE_CACHE:
            return Language._PARSE_CACHE[tag, normalize]

        data = {}
        # if the complete tag appears as something to normalize, do the
        # normalization right away. Smash case when checking, because the
        # case normalization that comes from parse_tag() hasn't been applied
        # yet.
        tag_lower = tag.lower()
        if normalize and tag_lower in LANGUAGE_REPLACEMENTS:
            tag = LANGUAGE_REPLACEMENTS[tag_lower]

        components = parse_tag(tag)

        for typ, value in components:
            if typ == 'extlang' and normalize and 'language' in data:
                # smash extlangs when possible
                minitag = '%s-%s' % (data['language'], value)
                norm = LANGUAGE_REPLACEMENTS.get(minitag.lower())
                if norm is not None:
                    data.update(
                        Language.get(norm, normalize).to_dict()
                    )
                else:
                    data.setdefault('extlangs', []).append(value)
            elif typ in {'extlang', 'variant', 'extension'}:
                data.setdefault(typ + 's', []).append(value)
            elif typ == 'language':
                if value == 'und':