--- a/mercurial/changelog.py	Mon Feb 21 13:03:43 2022 -0700
+++ b/mercurial/changelog.py	Mon Feb 21 13:08:28 2022 -0700
@@ -91,7 +91,7 @@
     return b'\n'.join([l.rstrip() for l in desc.splitlines()]).strip(b'\n')
 
 
-class appender(object):
+class appender:
     """the changelog index must be updated last on disk, so we use this class
     to delay writes to it"""
 
@@ -161,7 +161,7 @@
         return self.fp.__exit__(*args)
 
 
-class _divertopener(object):
+class _divertopener:
     def __init__(self, opener, target):
         self._opener = opener
         self._target = target
@@ -188,7 +188,7 @@
 
 
 @attr.s
-class _changelogrevision(object):
+class _changelogrevision:
     # Extensions might modify _defaultextra, so let the constructor below pass
     # it in
     extra = attr.ib()
@@ -204,7 +204,7 @@
     branchinfo = attr.ib(default=(_defaultextra[b'branch'], False))
 
 
-class changelogrevision(object):
+class changelogrevision:
     """Holds results of a parsed changelog revision.
 
     Changelog revisions consist of multiple pieces of data, including