def access_route(self) -> list[str]:
        """If a forwarded header exists this is a list of all ip addresses
        from the client ip to the last proxy server.
        """
        if "X-Forwarded-For" in self.headers:
            return self.list_storage_class(
                parse_list_header(self.headers["X-Forwarded-For"])
            )
        elif self.remote_addr is not None:
            return self.list_storage_class([self.remote_addr])
        return self.list_storage_class()
If a forwarded header exists this is a list of all ip addresses
        from the client ip to the last proxy server.
        
src/werkzeug/sansio/request.py