2to3 --fix=idioms
diff --git a/Lib/fontTools/misc/xmlWriter.py b/Lib/fontTools/misc/xmlWriter.py
index 52d9a5c..9246255 100644
--- a/Lib/fontTools/misc/xmlWriter.py
+++ b/Lib/fontTools/misc/xmlWriter.py
@@ -108,8 +108,7 @@
 	def stringifyattrs(self, *args, **kwargs):
 		if kwargs:
 			assert not args
-			attributes = kwargs.items()
-			attributes.sort()
+			attributes = sorted(kwargs.items())
 		elif args:
 			assert len(args) == 1
 			attributes = args[0]