diff --git a/spanet/dataset/evaluator.py b/spanet/dataset/evaluator.py
index 15df8b94..92545aea 100644
--- a/spanet/dataset/evaluator.py
+++ b/spanet/dataset/evaluator.py
@@ -29,9 +29,8 @@ def __init__(self, event_info: EventInfo):
             cluster_group = self.target_groups[names[0]]
             for name in names:
                 assert (
-                    self.target_groups[name] == cluster_group,
-                    "Invalid Symmetry Group. Invariant targets have different structures."
-                )
+                    self.target_groups[name] == cluster_group
+                ), "Invalid Symmetry Group. Invariant targets have different structures."
 
             cluster_groups.append((cluster_name, names, cluster_group))