From b4d0b39a9b4cd203bcc5b236dc96456e9658119a Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sun, 22 Sep 2019 13:32:41 +0300
Subject: bpo-38209: Simplify dataclasses.InitVar by using __class_getitem__().
 (GH-16255)

---
 Lib/dataclasses.py | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
index 9020c90..9135b07 100644
--- a/Lib/dataclasses.py
+++ b/Lib/dataclasses.py
@@ -199,11 +199,7 @@ _POST_INIT_NAME = '__post_init__'
 # https://bugs.python.org/issue33453 for details.
 _MODULE_IDENTIFIER_RE = re.compile(r'^(?:\s*(\w+)\s*\.)?\s*(\w+)')
 
-class _InitVarMeta(type):
-    def __getitem__(self, params):
-        return InitVar(params)
-
-class InitVar(metaclass=_InitVarMeta):
+class InitVar:
     __slots__ = ('type', )
 
     def __init__(self, type):
@@ -212,6 +208,9 @@ class InitVar(metaclass=_InitVarMeta):
     def __repr__(self):
         return f'dataclasses.InitVar[{self.type.__name__}]'
 
+    def __class_getitem__(cls, type):
+        return InitVar(type)
+
 
 # Instances of Field are only ever created from within this module,
 # and only from the field() function, although Field instances are
-- 
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