From 58ef146834496b2e4d2e52ea8d093ef47a205f2c Mon Sep 17 00:00:00 2001
From: Stefan van der Walt <stefan@sun.ac.za>
Date: Sun, 27 Apr 2014 04:05:52 +0200
Subject: [PATCH] Copy list of modules since it may change during iteration

---
 skimage/_shared/_warnings.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/skimage/_shared/_warnings.py b/skimage/_shared/_warnings.py
index 15680c76..99f2de0f 100644
--- a/skimage/_shared/_warnings.py
+++ b/skimage/_shared/_warnings.py
@@ -49,7 +49,7 @@ def all_warnings():
             f[0].f_locals['__warningregistry__'] = {}
     del frame
 
-    for mod in sys.modules.values():
+    for mod in list(sys.modules.values()):
         try:
             mod.__warningregistry__.clear()
         except AttributeError: