diff --git a/popmon/alerting/compute_tl_bounds.py b/popmon/alerting/compute_tl_bounds.py
index 1929537d..961e1601 100644
--- a/popmon/alerting/compute_tl_bounds.py
+++ b/popmon/alerting/compute_tl_bounds.py
@@ -231,7 +231,7 @@ def transform(self, test_data: dict) -> Tuple[Any, Any]:
                         feature,
                         test_df.columns,
                         pattern,
-                        rule=lambda _, feature, pattern: f"{feature}:{pattern}",
+                        rule=lambda _, feat, pat: f"{feat}:{pat}",
                     )
             # --- 2. tl bounds not explicitly defined for a particular feature,
             #        see if a wildcard match can be found.
@@ -240,7 +240,7 @@ def transform(self, test_data: dict) -> Tuple[Any, Any]:
                     feature,
                     test_df.columns,
                     pattern,
-                    rule=lambda _, __, pattern: pattern,
+                    rule=lambda _, __, pat: pat,
                 )
 
         return self.traffic_lights, self.traffic_light_funcs