code: def run_request_processors(self, request):
          
          if not getattr(self, 'request_processors', None):
              return
  
          for fn in reversed(list(self.request_processors.values())):
              r = fn(self, request)
              if r:
                  return r
docs: Before rendering a page, run all registered request processors. A
          request processor may peruse and modify the page or the request. It can
          also return a ``HttpResponse`` for shortcutting the rendering and
          returning that response immediately to the client.