code: async def postprocess_websocket(
          self,
          response: Optional[Response],
          websocket_context: Optional[WebsocketContext]=None,
      ) -> Response:
          
          websocket_ = (websocket_context or _websocket_ctx_stack.top).websocket
          functions = (websocket_context or _websocket_ctx_stack.top)._after_websocket_functions
          blueprint = websocket_.blueprint
          if blueprint is not None:
              functions = chain(functions, self.after_websocket_funcs[blueprint])
          functions = chain(functions, self.after_websocket_funcs[None])
  
          for function in functions:
              response = await function(response)
  
          session_ = (websocket_context or _request_ctx_stack.top).session
          if not self.session_interface.is_null_session(session_):
              if response is None and isinstance(session_, SecureCookieSession) and session_.modified:
                  self.logger.exception(
                      "Secure Cookie Session modified during websocket handling. "
                      "These modifications will be lost as a cookie cannot be set."
                  )
              else:
                  await self.save_session(session_, response)
          return response
docs: Postprocess the websocket acting on the response.
  
          Arguments:
              response: The response after the websocket is finalized.
              webcoket_context: The websocket context, optional as Flask
                  omits this argument.