--- a/hgext3rd/evolve/stablerange.py	Fri Mar 24 11:18:01 2017 +0100
+++ b/hgext3rd/evolve/stablerange.py	Fri Mar 24 11:20:42 2017 +0100
@@ -225,9 +225,10 @@
 class stablerange(object):
 
     def __init__(self):
+        # cache the 'depth' of a changeset, the size of '::rev'
         self._depthcache = {}
+        # cache the standard stable subranges or a range
         self._subrangescache = {}
-
         # To slices merge, we need to walk their descendant in reverse stable
         # sort order. For now we perform a full stable sort their descendant
         # and then use the relevant top most part. This order is going to be