Close #14386: Register types.MappingProxyType as a Mapping
diff --git a/Lib/collections/abc.py b/Lib/collections/abc.py
index 37a813a..d17cfdc 100644
--- a/Lib/collections/abc.py
+++ b/Lib/collections/abc.py
@@ -43,7 +43,7 @@
 dict_values = type({}.values())
 dict_items = type({}.items())
 ## misc ##
-dict_proxy = type(type.__dict__)
+mappingproxy = type(type.__dict__)
 
 
 ### ONE-TRICK PONIES ###
@@ -405,6 +405,8 @@
     def __ne__(self, other):
         return not (self == other)
 
+Mapping.register(mappingproxy)
+
 
 class MappingView(Sized):