diff --git a/src/_zkapauthorizer/tests/test_lease_maintenance.py b/src/_zkapauthorizer/tests/test_lease_maintenance.py
index 8f64c0f8670bca2179f12f3478700409442c64b4..0c1452d9a527400d87eeacec824bd64168b465a1 100644
--- a/src/_zkapauthorizer/tests/test_lease_maintenance.py
+++ b/src/_zkapauthorizer/tests/test_lease_maintenance.py
@@ -131,6 +131,8 @@ def dummy_maintain_leases():
 @attr.s
 class DummyStorageServer(object):
     """
+    A dummy implementation of ``IStorageServer`` from Tahoe-LAFS.
+
     :ivar dict[bytes, datetime] buckets: A mapping from storage index to lease
         expiration time for shares at that storage index.
     """