diff --git a/library/config_util.py b/library/config_util.py
index afc9be75..47a3ac82 100644
--- a/library/config_util.py
+++ b/library/config_util.py
@@ -167,7 +167,7 @@ class ConfigSanitizer:
     "enable_bucket": bool,
     "max_bucket_reso": int,
     "min_bucket_reso": int,
-    "resolution": functools.partial(__validate_and_convert_scalar_or_twodim, int),
+    "resolution": functools.partial(__validate_and_convert_scalar_or_twodim.__func__, int),
   }
 
   # options handled by argparse but not handled by user config