--- a/mercurial/mail.py	Sun Oct 06 16:39:13 2019 -0400
+++ b/mercurial/mail.py	Sun Oct 06 16:55:18 2019 -0400
@@ -19,7 +19,10 @@
 import time
 
 from .i18n import _
-from .pycompat import open
+from .pycompat import (
+    getattr,
+    open,
+)
 from . import (
     encoding,
     error,