Replace iteritems with six helper

Carlos Diaz-Padron · Carlos Diaz-Padron · commit d815c8de3092 · 2016-01-28T15:38:27.000-08:00
diff --git a/twilio/values.py b/twilio/values.py
@@ -1,6 +1,7 @@
+from six import iteritems
 unset = object()
 
 
 def of(d):
-    return {k: v for k, v in d.iteritems() if v != unset}
+    return {k: v for k, v in iteritems(d) if v != unset}
 
