[3.15] gh-149083: Convert `_initial_missing` for pure py `reduce` to `sentinel` ...

gh-149083: Convert `_initial_missing` for pure py `reduce` to `sentinel` (GH-149536)
(cherry picked from commit bc8cf07d8dbb4341955dc85d9b2bf273ec5852c7)

Co-authored-by: sobolevn <mail@sobolevn.me>

diff --git a/Lib/functools.py b/Lib/functools.py
index cd374631f167925b9a495a2d6e6d75d910a80ebb..e03a77f204b5443268c5577dc5f2d3c3a6e0d632 100644 (file)
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -232,7 +232,7 @@ except ImportError:
 ### reduce() sequence to a single item
 ################################################################################
 
-_initial_missing = object()
+_initial_missing = sentinel('_initial_missing')
 
 def reduce(function, sequence, initial=_initial_missing):
     """