#!/usr/local/bin/python2
import xml.etree.ElementTree as et
r = et.XML('<r><a></a>ahhnfh<b></b>fdsfgh</r>')
for i in xrange(300000):
  ''.join(c.tail for c in r if c.tail is not None)
print ''.join(c.tail for c in r if c.tail is not None)