def evaluate(self):
        """
        Returns:
            dict: has a key "segm", whose value is a dict of "AP" and "AP50".
        """
        comm.synchronize()
        if comm.get_rank() > 0:
            return
        import cityscapesscripts.evaluation.evalInstanceLevelSemanticLabeling as cityscapes_eval

        self._logger.info("Evaluating results under {} ...".format(self._temp_dir))

        # set some global states in cityscapes evaluation API, before evaluating
        cityscapes_eval.args.predictionPath = os.path.abspath(self._temp_dir)
        cityscapes_eval.args.predictionWalk = None
        cityscapes_eval.args.JSONOutput = False
        cityscapes_eval.args.colorized = False
        cityscapes_eval.args.gtInstancesFile = os.path.join(self._temp_dir, "gtInstances.json")

        # These lines are adopted from
        # https://github.com/mcordts/cityscapesScripts/blob/master/cityscapesscripts/evaluation/evalInstanceLevelSemanticLabeling.py # noqa
        gt_dir = PathManager.get_local_path(self._metadata.gt_dir)
        groundTruthImgList = glob.glob(os.path.join(gt_dir, "*", "*_gtFine_instanceIds.png"))
        assert len(
            groundTruthImgList
        ), "Cannot find any ground truth images to use for evaluation. Searched for: {}".format(
            cityscapes_eval.args.groundTruthSearch
        )
        predictionImgList = []
        for gt in groundTruthImgList:
            predictionImgList.append(cityscapes_eval.getPrediction(gt, cityscapes_eval.args))
        results = cityscapes_eval.evaluateImgLists(
            predictionImgList, groundTruthImgList, cityscapes_eval.args
        )["averages"]

        ret = OrderedDict()
        ret["segm"] = {"AP": results["allAp"] * 100, "AP50": results["allAp50%"] * 100}
        self._working_dir.cleanup()
        return ret

        Returns:
            dict: has a key "segm", whose value is a dict of "AP" and "AP50".
        
video_chat_with_ChatGPT/models/grit_src/third_party/CenterNet2/detectron2/evaluation/cityscapes_evaluation.py