Add minor fixes

Author: Hmnt39

cognite/extractorutils/unstable/core/base.py

@@ -283,10 +283,8 @@ def _load_metrics(self, metrics_class: type[BaseMetrics] | None = None) -> BaseM
         if Extractor._metrics_singleton is not None:
             return Extractor._metrics_singleton
 
-        if metrics_class:
-            metrics_instance = safe_get(metrics_class)
-        else:
-            metrics_instance = BaseMetrics(extractor_name=self.EXTERNAL_ID, extractor_version=self.VERSION)
+        cls_to_use = metrics_class or BaseMetrics
+        metrics_instance = safe_get(cls_to_use, extractor_name=self.EXTERNAL_ID, extractor_version=self.VERSION)
 
         Extractor._metrics_singleton = metrics_instance
         return metrics_instance