def _validate_date_style(date_style: str) -> None:
    """
    Validates the given date style.

    Args:
        date_style (str): The date style to be validated.

    Raises:
        ValueError: If `date_style` is not a valid value.

    Returns:
        None
    """
    if date_style not in _get_date_formats_dict():
        raise ValueError(f"date_style must be one of: {', '.join(_get_date_formats_dict().keys())}")

    Validates the given date style.

    Args:
        date_style (str): The date style to be validated.

    Raises:
        ValueError: If `date_style` is not a valid value.

    Returns:
        None
    
great_tables/_formats.py