diff --git a/.ruff.toml b/.ruff.toml
index 000e09088..5709980c4 100644
--- a/.ruff.toml
+++ b/.ruff.toml
@@ -17,6 +17,7 @@ select = [
 ]
 extend-ignore = [
   "E712",
+  "E721",
   # pycodestyle (E, W)
   "E501", # LineTooLong                             # TODO! fix
   # pytest (PT)