diff -r 38f08eaba6b0 -r c35c0f54f420 mercurial/obsutil.py
--- a/mercurial/obsutil.py	Mon Jul 03 15:34:00 2017 +0200
+++ b/mercurial/obsutil.py	Mon Jul 03 15:34:10 2017 +0200
@@ -602,6 +602,11 @@
         verb = 'split'
     return verb
 
+def markersdates(markers):
+    """returns the list of dates for a list of markers
+    """
+    return [m[4] for m in markers]
+
 def markersusers(markers):
     """ Returns a sorted list of markers users without duplicates
     """