diff --git a/lib/galaxy/util/compression_utils.py b/lib/galaxy/util/compression_utils.py
index 2282a7578880..5b395a6b6251 100644
--- a/lib/galaxy/util/compression_utils.py
+++ b/lib/galaxy/util/compression_utils.py
@@ -34,7 +34,7 @@
 try:
     from isal import isal_zlib
 except ImportError:
-    isal_zlib = None  # type: ignore[assignment]
+    isal_zlib = None  # type: ignore[assignment,unused-ignore]
 
 
 log = logging.getLogger(__name__)