def get_schema(cls: type) -> PlainConfigSchema:
    """Extract ConfigOptions defined in a class (used just as a container) and put them into a schema tuple."""
    if issubclass(cls, Config):
        return cls._schema
    return tuple((k, v) for k, v in cls.__dict__.items() if isinstance(v, BaseConfigOption))
Extract ConfigOptions defined in a class (used just as a container) and put them into a schema tuple.
mkdocs/config/base.py