def METHOD_NAME(cls, filter_values):
    """ Here we assume that filter_values has already been run through validate_filter_values. """
    if isinstance(filter_values, list):
        # Legacy is treated as a "require" filter.
        require = [[f] for f in filter_values]
        exclude = []
    elif isinstance(filter_values, dict):
        # PSCCodeObject
        require = filter_values.get("require") or []
        exclude = filter_values.get("exclude") or []
    else:
        raise UnprocessableEntityException(f"psc_codes must be an array or object")
    return require, exclude