diff --git a/saqc/funcs/flagtools.py b/saqc/funcs/flagtools.py
index 23341ec2b3df61d1beb5b28fb0c86fa798fb5adc..80420a1cdd18ac939a7981a0cda961219e263b3a 100644
--- a/saqc/funcs/flagtools.py
+++ b/saqc/funcs/flagtools.py
@@ -403,7 +403,7 @@ class FlagtoolsMixin:
             will be removed in version 2.5 of SaQC. Please use
             'SaQC.concatFlags(field={field}, target={target}, method="match", squeeze=False)'
             instead""",
-            DeprecationWarning
+            DeprecationWarning,
         )
         return self.concatFlags(field, target=target, method="match", squeeze=False)