code: def documentation_404(self, base_url=None):
          
          base_url = self.base_url if base_url is None else base_url
  
          def handle_404(request, response, *args, **kwargs):
              url_prefix = request.forwarded_uri[:-1]
              if request.path and request.path != "/":
                  url_prefix = request.forwarded_uri.split(request.path)[0]
  
              to_return = OrderedDict()
              to_return['404'] = ("The API call you tried to make was not defined. "
                                  "Here's a definition of the API to help you get going :)")
              to_return['documentation'] = self.documentation(base_url, self.determine_version(request, False),
                                                              prefix=url_prefix)
  
              if self.output_format == hug.output_format.json:
                  response.data = hug.output_format.json(to_return, indent=4, separators=(',', ': '))
                  response.content_type = 'application/json; charset=utf-8'
              else:
                  response.data = self.output_format(to_return, request=request, response=response)
                  response.content_type = self.output_format.content_type
  
              response.status = falcon.HTTP_NOT_FOUND
  
          handle_404.interface = True
          return handle_404
docs: Returns a smart 404 page that contains documentation for the written API