diff --git a/src/_zkapauthorizer/tests/strategies.py b/src/_zkapauthorizer/tests/strategies.py
index 6b21896d9a0c70d15766044cff5cd9ef68064d3d..9f9e254f170517e1e06c932aca9db391c4aca517 100644
--- a/src/_zkapauthorizer/tests/strategies.py
+++ b/src/_zkapauthorizer/tests/strategies.py
@@ -221,6 +221,9 @@ def vouchers():
 
 
 def voucher_objects():
+    """
+    Build ``Voucher`` instances.
+    """
     return builds(
         Voucher,
         number=vouchers(),