def bdday_to_date(bdday : str) -> str :
    """
    Convert Buddhist year "DDMMYY" to "YYYY-MM-DD"
    """
    if len(bdday) != 6 : 
        print("Buddhist Date must be 6 digits")
        raise ValueError
    # Convert 2 digit buddhist year to 4 digit year
    year = 1957 + int(bdday[-2:])
    return f"{year}-{bdday[2:4]}-{bdday[:2]}"