With this diff, everything works as expected:

```diff
diff --git a/scripts/serve_example_primary.js b/scripts/serve_example_primary.js
index 51711bd..79debe9 100755
--- a/scripts/serve_example_primary.js
+++ b/scripts/serve_example_primary.js
@@ -20,17 +20,20 @@ require("jwcrypto/lib/algs/ds");
 
 var exampleServer = express.createServer();
 const API_PREFIX = '/api';
+const SESSION_DURATION_MS = 1 * 60 * 60 * 1000;
 
 exampleServer.use(express.cookieParser());
 
 exampleServer.use(API_PREFIX, sessions({
   secret: "this secret, isn't very secret",
   cookieName: 'example_browserid_primary',
+  requestKey: 'session',
+  duration: SESSION_DURATION_MS,
   cookie: {
     path: '/api',
     httpOnly: true,
     secure: false,
-    maxAge: 1 * 60 * 60 * 1000
+    maxAge: SESSION_DURATION_MS
   }
 }));
 
````