remove _get_metric_scope

mmengine/hooks/checkpoint_hook.py

@@ -2,7 +2,6 @@
 import os.path as osp
 import re
 import warnings
-from collections import OrderedDict
 from math import inf
 from pathlib import Path
 from typing import Callable, Dict, List, Optional, Sequence, Union
@@ -297,18 +296,6 @@ class CheckpointHook(Hook):
         """
         self._save_best_checkpoint(runner, metrics)
 
-    def _get_metric_score(self, metrics, key_indicator):
-        eval_res = OrderedDict()
-        if metrics is not None:
-            eval_res.update(metrics)
-        if len(eval_res) == 0:
-            warnings.warn(
-                'Since `eval_res` is an empty dict, the behavior to save '
-                'the best checkpoint will be skipped in this evaluation.')
-            return None
-
-        return eval_res[key_indicator]
-
     def _save_checkpoint(self, runner) -> None:
         """Save the current checkpoint and delete outdated checkpoint.
 
@@ -385,7 +372,7 @@ class CheckpointHook(Hook):
         # save best logic
         # get score from messagehub
         for key_indicator, rule in zip(self.key_indicators, self.rules):
-            key_score = self._get_metric_score(metrics, key_indicator)
+            key_score = metrics.get(key_indicator, None)
 
             if len(self.key_indicators) == 1:
                 best_score_key = 'best_score'