diff -r 55d132525155 -r 642e31cb55f0 mercurial/revlogutils/deltas.py
--- a/mercurial/revlogutils/deltas.py	Mon Feb 21 13:03:43 2022 -0700
+++ b/mercurial/revlogutils/deltas.py	Mon Feb 21 13:08:28 2022 -0700
@@ -38,7 +38,7 @@
 LIMIT_DELTA2TEXT = 2
 
 
-class _testrevlog(object):
+class _testrevlog:
     """minimalist fake revlog to use in doctests"""
 
     def __init__(self, data, density=0.5, mingap=0, snapshot=()):
@@ -544,7 +544,7 @@
 
 
 @attr.s(slots=True, frozen=True)
-class _deltainfo(object):
+class _deltainfo:
     distance = attr.ib()
     deltalen = attr.ib()
     data = attr.ib()
@@ -927,7 +927,7 @@
         yield (prev,)
 
 
-class deltacomputer(object):
+class deltacomputer:
     def __init__(self, revlog):
         self.revlog = revlog