@classmethod
def fromisoformat(cls, date_string: str):
    """Construct Hijri object from an ISO formatted Hijri date
        'YYYY-MM-DD'.

        :param date_string: Hijri date in ISO format ``YYYY-MM-DD``
        :type date_string: str
        :return: Hijri date object
        :rtype: Hijri
        """
    year = int(date_string[0:4])
    month = int(date_string[5:7])
    day = int(date_string[8:10])
    return cls(year, month, day)
