Issue #11297: Add collections.ChainMap()
diff --git a/Lib/string.py b/Lib/string.py
index 2bc5d00..d4f9cd9 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -46,7 +46,7 @@
 
 ####################################################################
 import re as _re
-from collections import _ChainMap
+from collections import ChainMap
 
 class _TemplateMetaclass(type):
     pattern = r"""
@@ -100,7 +100,7 @@
         if not args:
             mapping = kws
         elif kws:
-            mapping = _ChainMap(kws, args[0])
+            mapping = ChainMap(kws, args[0])
         else:
             mapping = args[0]
         # Helper function for .sub()
@@ -126,7 +126,7 @@
         if not args:
             mapping = kws
         elif kws:
-            mapping = _ChainMap(kws, args[0])
+            mapping = ChainMap(kws, args[0])
         else:
             mapping = args[0]
         # Helper function for .sub()