import sys
from genshi.template import MarkupTemplate, Context

class Indexable(object):
  def __str__(self):
    return "foo"
  
  def __getitem__(self, key):
    print key
    return None

  #def __iter__(self): return None

context = { 'contextbomb': Indexable() }

text = """
<div xmlns="http://www.w3.org/1999/xhtml"
  xmlns:py="http://genshi.edgewall.org/">
  ${contextbomb}
</div>
"""

print text

tmpl = MarkupTemplate(text)
stream = tmpl.generate(**context)
print stream.render('xhtml')