def is_date(stamp):
    """
    This function will return True or False, depending if the supplied stamp
    can be interpreted as a date string of format DDMMYYYY
    """
    if isinstance(stamp, str):
        if len(stamp) == 8:
            if stamp.isdigit():
                DD = int(stamp[:2])
                if DD > 31:
                    return False
                MM = int(stamp[2:4])
                if MM > 12:
                    return False
            else:
                return False
        else:
            return False
    else:
        return False
    return True