def METHOD_NAME(value_tag: str, taxonomy_type: str) -> Optional[str]:
    """Return the canonical taxonomized value of a `value_tag` (if any) or
    return None if no match was found or if the type is unsupported.
    Currently it only works for brand and label.
    """
    if taxonomy_type not in (TaxonomyType.brand.name, TaxonomyType.label.name):
        return None
    taxonomy = get_taxonomy(taxonomy_type)
    if value_tag in taxonomy:
        return value_tag
    return get_taxonomy_mapping(taxonomy_type).get(value_tag)