diff --git a/tensorflow/python/keras/saving/metrics_serialization_test.py b/tensorflow/python/keras/saving/metrics_serialization_test.py
index 0a15d3e466d..10eee4d4175 100644
--- a/tensorflow/python/keras/saving/metrics_serialization_test.py
+++ b/tensorflow/python/keras/saving/metrics_serialization_test.py
@@ -220,7 +220,7 @@ class MetricsSerialization(keras_parameterized.TestCase):
     def get_instance(x):
       if isinstance(x, str):
         return x
-      if issubclass(x, metrics.Metric):
+      if isinstance(x, type) and issubclass(x, metrics.Metric):
         return x()
       return x