From 017117778ec477205eaba6acab951951808a60a5 Mon Sep 17 00:00:00 2001
From: Armin Ronacher <armin.ronacher@active-4.com>
Date: Mon, 25 Apr 2011 16:02:35 +0200
Subject: [PATCH] Document that None skips in query strings.  This fixes #224

---
 flask/helpers.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/flask/helpers.py b/flask/helpers.py
index 418c4b17..ec513d8f 100644
--- a/flask/helpers.py
+++ b/flask/helpers.py
@@ -166,7 +166,8 @@ def url_for(endpoint, **values):
     ==================== ======================= =============================
 
     Variable arguments that are unknown to the target endpoint are appended
-    to the generated URL as query arguments.
+    to the generated URL as query arguments.  If the value of a query argument
+    is `None`, the whole pair is skipped.
 
     For more information, head over to the :ref:`Quickstart <url-building>`.