How to use the datafiles.converters.Dictionary.subclass function in datafiles

if cls.__origin__ == list:
            try:
                converter = map_type(cls.__args__[0])
            except TypeError as e:
                if '~T' in str(e):
                    e = TypeError(f"Type is required with 'List' annotation")
                raise e from None
            else:
                converter = List.subclass(converter)

        if cls.__origin__ == dict:
            log.warn("Schema enforcement not possible with 'Dict' annotation")
            key = map_type(cls.__args__[0])
            value = map_type(cls.__args__[1])

            converter = Dictionary.subclass(key, value)

        elif cls.__origin__ == Union:
            converter = map_type(cls.__args__[0])
            assert len(cls.__args__) == 2
            assert cls.__args__[1] == type(None)
            converter = converter.as_optional()

        if converter:
            log.debug(f'Mapped {cls!r} to new converter: {converter}')
            return converter

        raise TypeError(f'Unsupported container type: {cls.__origin__}')

    else:
        for converter in Converter.__subclasses__():
            if converter.TYPE == cls: