def NotFound(message=None):
 if message:
  return _NotFound(message)
 elif ctx.get('app_stack'):
  return ctx.app_stack[(-1)].notfound()
 else:
  return _NotFound()

def NotFound ( message = None ) : if message : return _NotFound ( message ) elif ctx . get ( 'app_stack' ) : return ctx . app_stack [ ( - 1 ) ] . notfound ( ) else : return _NotFound ( )
returns httperror with 404 not found error from the active application .