diff --git a/src/_zkapauthorizer/_plugin.py b/src/_zkapauthorizer/_plugin.py
index ddcf4d2263cade1e6722fc59840da0cbfda71651..503d43a34a9cbafafc5e4a84f0d4405f39b734c6 100644
--- a/src/_zkapauthorizer/_plugin.py
+++ b/src/_zkapauthorizer/_plugin.py
@@ -202,6 +202,8 @@ def make_safe_writer(metrics_path, registry):
         except Exception:
             pass
 
+    return safe_writer
+
 
 _init_storage = _Client.__dict__["init_storage"]