diff --git a/fusion_bench/method/slerp/slerp.py b/fusion_bench/method/slerp/slerp.py
index d69ad2dd..321a37c3 100644
--- a/fusion_bench/method/slerp/slerp.py
+++ b/fusion_bench/method/slerp/slerp.py
@@ -51,7 +51,7 @@ class SlerpMergeAlgorithm(BaseAlgorithm):
     General purpose implementation of Slerp (Spherical Linear Interpolation) for PyTorch models.
     """
 
-    _config_mapping = BaseAlgorithm._config_mapping + {
+    _config_mapping = BaseAlgorithm._config_mapping | {
         "t": "t",
         "DOT_THRESHOLD": "DOT_THRESHOLD",
         "epsilon": "epsilon",