--- a/mercurial/localrepo.py	Thu Aug 02 22:44:41 2018 +0300
+++ b/mercurial/localrepo.py	Fri Apr 13 23:37:53 2018 -0700
@@ -860,7 +860,8 @@
     def __contains__(self, changeid):
         """True if the given changeid exists
 
-        error.LookupError is raised if an ambiguous node specified.
+        error.AmbiguousPrefixLookupError is raised if an ambiguous node
+        specified.
         """
         try:
             self[changeid]