error

WARNING:tornado.general:400 POST /2055047/edit (127.0.0.1): Missing argument featured_place
WARNING:tornado.access:400 POST /2055047/edit (127.0.0.1) 3698.63ms
ERROR:tornado.application:Uncaught exception in write_error
Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/tornado-4.0.2-py2.7-macosx-10.9-intel.egg/tornado/web.py", line 929, in send_error
    self.write_error(status_code, **kwargs)
  File "/Users/andrey/Work/forum/server/lib/tornado_mvc.py", line 109, in write_error
    self.render('errors/500.html', **data)
  File "/Library/Python/2.7/site-packages/tornado-4.0.2-py2.7-macosx-10.9-intel.egg/tornado/web.py", line 665, in render
    html = self.render_string(template_name, **kwargs)
  File "/Library/Python/2.7/site-packages/tornado-4.0.2-py2.7-macosx-10.9-intel.egg/tornado/web.py", line 770, in render_string
    namespace = self.get_template_namespace()
  File "/Users/andrey/Work/forum/server/lib/tornado_mvc.py", line 176, in get_template_namespace
    namespace = super(BaseHandler, self).get_template_namespace()
  File "/Library/Python/2.7/site-packages/tornado-4.0.2-py2.7-macosx-10.9-intel.egg/tornado/web.py", line 793, in get_template_namespace
    namespace.update(self.ui)
TypeError: 'NoneType' object is not iterable