bpo-43772: Fix TypeVar.__ror__ (GH-25339)

diff --git a/Lib/typing.py b/Lib/typing.py
index 6461ba2..a24c01f 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -648,8 +648,8 @@ def __init__(self, bound, covariant, contravariant):
     def __or__(self, right):
         return Union[self, right]
 
-    def __ror__(self, right):
-        return Union[self, right]
+    def __ror__(self, left):
+        return Union[left, self]
 
     def __repr__(self):
         if self.__covariant__: