"""Convert to and from Roman numeralsThis program is part of "Dive Into Python", a free Python book forexperienced programmers.  Visit http://diveintopython.org/ for thelatest version."""__author__ = "Mark Pilgrim (mark@diveintopython.org)"__version__ = "$Revision: 1.2 $"__date__ = "$Date: 2004/05/05 21:57:20 $"__copyright__ = "Copyright (c) 2001 Mark Pilgrim"__license__ = "Python"#Define exceptionsclass RomanError(Exception): passclass OutOfRangeError(RomanError): passclass NotIntegerError(RomanError): passclass InvalidRomanNumeralError(RomanError): pass#Define digit mappingromanNumeralMap = (('M',  1000),                   ('CM', 900),                   ('D',  500),                   ('CD', 400),                   ('C',  100),                   ('XC', 90),                   ('L',  50),                   ('XL', 40),                   ('X',  10),                   ('IX', 9),                   ('V',  5),                   ('IV', 4),                   ('I',  1))def toRoman(n):    """convert integer to Roman numeral"""    result = ""    for numeral, integer in romanNumeralMap:        while n >= integer:            result += numeral            n -= integer    return resultdef fromRoman(s):    """convert Roman numeral to integer"""    pass