--- a/mercurial/tags.py	Mon May 16 21:30:32 2016 +0000
+++ b/mercurial/tags.py	Mon May 16 21:30:53 2016 +0000
@@ -292,7 +292,7 @@
     cachehash = None
     if cachefile:
         try:
-            validline = cachelines.next()
+            validline = next(cachelines)
             validline = validline.split()
             cacherev = int(validline[0])
             cachenode = bin(validline[1])