#!/usr/bin/env python
     # encoding: utf-8
     #
     # Copyright (c) 2010 Doug Hellmann.  All rights reserved.
     #
     """Substitute based on patterns.
     """
     #end_pymotw_header
     
     import re
     
     bold = re.compile(r'\*{2}(.*?)\*{2}', re.UNICODE)
     
     text = 'Make this **bold**.  This **too**.'
     
     print 'Text:', text
     print 'Bold:', bold.sub(r'<b>\1</b>', text, count=1)