diff --git a/test_opensearchpy/test_serializer.py b/test_opensearchpy/test_serializer.py
index d425fabf..4823a1d4 100644
--- a/test_opensearchpy/test_serializer.py
+++ b/test_opensearchpy/test_serializer.py
@@ -111,9 +111,7 @@ class TestJSONSerializer(TestCase):
             np.float32,
             np.float64,
         ):
-            self.assertRegexpMatches(
-                ser.dumps({"d": np_type(1.2)}), r'^\{"d":1\.2[\d]*}$'
-            )
+            self.assertRegex(ser.dumps({"d": np_type(1.2)}), r'^\{"d":1\.2[\d]*}$')
 
     def test_serializes_numpy_datetime(self) -> None:
         requires_numpy_and_pandas()