foo.py

class Profile(db.Model):
  user = db.UserProperty()
	nickname = db.TextProperty()
	desc = db.TextProperty()
	pic = db.TextProperty()

	def html_desc(self):
		def rep(match):
			sub = match.group(1)
			if '|' not in sub:
				return '[' + sub + ']'
			else:
				color, text = sub.split('|', 1)
				color = color.replace('<', '\0')
				color = color.replace('>', '\x02')
				color = color.replace('"', '\x01')
				return '\0span style=\x01color: %s\x01\x02%s\x00/span\x02' % (color.strip(), text.strip())
		desc = re.sub(r'\[(.*?)\]', rep, self.desc)
		desc = desc.replace('<', '&lt;')
		desc = desc.replace('>', '&gt;')
		desc = desc.replace('"', '&quot;')
		desc = desc.replace('\0', '<')
		desc = desc.replace('\x02', '>')
		desc = desc.replace('\x01', '"')
		desc = desc.replace('\n', '<br>')
		return desc