Issue 25147: add reason for using _collections

diff --git a/Lib/enum.py b/Lib/enum.py
index 6284b9bb7eb0090773d6ed1f5ba7aaf38a6edd16..8d04e2d718617fbcdbfa4a8fd1b8b172240d6488 100644 (file)
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -1,6 +1,7 @@
 import sys
 from types import MappingProxyType, DynamicClassAttribute
 
+# try _collections first to reduce startup cost
 try:
     from _collections import OrderedDict
 except ImportError: