--- a/hgext3rd/topic/compat.py	Fri Nov 15 11:37:34 2019 +0700
+++ b/hgext3rd/topic/compat.py	Fri Nov 15 11:48:17 2019 +0700
@@ -8,22 +8,11 @@
 from __future__ import absolute_import
 
 from mercurial import (
-    obsolete,
     pycompat,
     registrar,
     util,
 )
 
-successorssets = None
-try:
-    from mercurial import obsutil
-    successorssets = getattr(obsutil, 'successorssets', None)
-except ImportError:
-    pass
-
-if successorssets is None:
-    successorssets = obsolete.successorssets
-
 if pycompat.ispy3:
     def branchmapitems(branchmap):
         return branchmap.items()