diff --git a/python/ray/util/metrics.py b/python/ray/util/metrics.py
index e7a07b950..4c5686ba0 100644
--- a/python/ray/util/metrics.py
+++ b/python/ray/util/metrics.py
@@ -37,10 +37,9 @@ class Metric:
         # The Cython metric class. This should be set in the child class.
         self._metric = None
 
-        if type(self._tag_keys) != tuple:
-            raise ValueError(
-                "tag_keys should be a tuple type, "
-                f"but {type(self._tag_keys)} type was specified instead.")
+        if not isinstance(self._tag_keys, tuple):
+            raise ValueError("tag_keys should be a tuple type, got: "
+                             f"{type(self._tag_keys)}")
 
     def set_default_tags(self, default_tags: Dict[str, str]):
         """Set default tags of metrics.