text: """Convert to and from Roman numerals
  
  This program is part of "Dive Into Python", a free Python book for
  experienced programmers.  Visit http://diveintopython.org/ for the
  latest 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 exceptions
  class RomanError(Exception): pass
  class OutOfRangeError(RomanError): pass
  class NotIntegerError(RomanError): pass
  class InvalidRomanNumeralError(RomanError): pass
  
  def toRoman(n):
      """convert integer to Roman numeral"""
      pass
  
  def fromRoman(s):
      """convert Roman numeral to integer"""
      pass
  