diff -r 8197b395710e -r 4aa72cdf616f mercurial/utils/procutil.py
--- a/mercurial/utils/procutil.py	Tue Oct 08 19:35:30 2019 -0700
+++ b/mercurial/utils/procutil.py	Sun Oct 06 20:17:41 2019 -0700
@@ -259,8 +259,8 @@
     (portable, not much used).
     """
     return (
-        pycompat.safehasattr(sys, b"frozen")
-        or pycompat.safehasattr(sys, b"importers")  # new py2exe
+        pycompat.safehasattr(sys, "frozen")
+        or pycompat.safehasattr(sys, "importers")  # new py2exe
         or imp.is_frozen(r"__main__")  # old py2exe
     )  # tools/freeze