start_year 1860 end_year datetime now year year max movie year start_y

        start_year = 1860
        end_year = datetime.now().year
        year = max(movie.year, start_year)
        year = min(year, end_year)

        FACTOR = 0 
        dividend = (year - start_year) - (end_year - year) * FACTOR
        divisor = end_year - start_year
        delta = dividend / divisor

        self.rating *= delta