The message accompanying the TypeError exception on a readonly
attribute changed again.
diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py
index 72a70ec..2476a27 100644
--- a/Lib/test/test_generators.py
+++ b/Lib/test/test_generators.py
@@ -405,7 +405,7 @@
 >>> i.gi_running = 42
 Traceback (most recent call last):
   ...
-TypeError: 'generator' object has only read-only attributes (assign to .gi_running)
+TypeError: readonly attribute
 >>> def g():
 ...     yield me.gi_running
 >>> me = g()