diff --git a/src/ZODB/tests/TransactionalUndoStorage.py b/src/ZODB/tests/TransactionalUndoStorage.py
index 3292d1cc14effb7ebd7bb7b71e71f2b5f439837e..b49080feb25cd69860ba31b52f22819a59265c67 100644
--- a/src/ZODB/tests/TransactionalUndoStorage.py
+++ b/src/ZODB/tests/TransactionalUndoStorage.py
@@ -1,10 +1,14 @@
+# Check transactionalUndo().  Any storage that supports transactionalUndo()
+# must pass these tests.
 
-import BasicStorage, pickle
+import pickle
 from ZODB import POSException
+
 ZERO = '\0'*8
 
-class TransactionalUndoStorage(BasicStorage.BasicStorage):
 
+
+class TransactionalUndoStorage:
     def checkSimpleTransactionalUndo(self):
         oid = self._storage.new_oid()
         revid = self._dostore(oid, data=23)