diff --git a/bench/release.py b/bench/release.py
index 02a32ff6..ebf60f6a 100755
--- a/bench/release.py
+++ b/bench/release.py
@@ -39,7 +39,7 @@ def release(bench_path, app, bump_type, from_branch, to_branch,
 		branches_to_update.update(config.get('branches_to_update'))
 
 	if config.get('releasable_branches'):
-		releasable_branches.extend(config.get('releasable_branches'),[])
+		releasable_branches.extend(config.get('releasable_branches',[]))
 
 	validate(bench_path, config)