def _get_century_code(year: int) -> str:
        """Returns the century code for a given year"""
        if 2000 <= year < 3000:
            separator = "A"
        elif 1900 <= year < 2000:
            separator = "-"
        elif 1800 <= year < 1900:
            separator = "+"
        else:
            raise ValueError("Finnish SSN do not support people born before the year 1800 or after the year 2999")
        return separator
Returns the century code for a given year
faker/providers/ssn/fi_FI/__init__.py