From 606ab86c0e11eb00fc276c694bff9d7f9239d538 Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Wed, 7 Dec 2016 13:31:20 +0200
Subject: [PATCH] Change order of io.UnsupportedOperation base classes. This
 makes tests passing after changes by issue #5322.

---
 Lib/_pyio.py            | 2 +-
 Modules/_io/_iomodule.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 0d98b744768..f2fe4471436 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -276,7 +276,7 @@ class OpenWrapper:
 try:
     UnsupportedOperation = io.UnsupportedOperation
 except AttributeError:
-    class UnsupportedOperation(ValueError, OSError):
+    class UnsupportedOperation(OSError, ValueError):
         pass
 
 
diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
index 65c955ac698..e9f22afb504 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -654,7 +654,7 @@ PyInit__io(void)
     /* UnsupportedOperation inherits from ValueError and IOError */
     state->unsupported_operation = PyObject_CallFunction(
         (PyObject *)&PyType_Type, "s(OO){}",
-        "UnsupportedOperation", PyExc_ValueError, PyExc_IOError);
+        "UnsupportedOperation", PyExc_OSError, PyExc_ValueError);
     if (state->unsupported_operation == NULL)
         goto fail;
     Py_INCREF(state->unsupported_operation);