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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 async def process_response( self, response: Response, request_context: Optional[RequestContext]=None, ) -> Response: """Postprocess the request acting on the response. Arguments: response: The response after the request is finalized. request_context: The request context, optional as Flask omits this argument. """

        request_ = (request_context or _request_ctx_stack.top).request
        functions = (request_context or _request_ctx_stack.top)._after_request_functions
        blueprint = request_.blueprint
        if blueprint is not None:
            functions = chain(functions, self.after_request_funcs[blueprint])
        functions = chain(functions, self.after_request_funcs[None])

        for function in functions:
            response = await function(response)

        session_ = (request_context or _request_ctx_stack.top).session
        if not self.session_interface.is_null_session(session_):
            await self.save_session(session_, response)
        return response