def storage_cb(self, key, value, handle, connection):
        self.send_response(handle, connection, None if value == None else json.dumps(value),
                           status=calvinresponse.NOT_FOUND if None else calvinresponse.OK)
dataset/ETHPy150Open EricssonResearch/calvin-base/calvin/runtime/north/calvincontrol.py/CalvinControl.storage_cb/operator `is` -> `==`