Change order of io.UnsupportedOperation base classes.
This makes tests passing after changes by issue #5322.
diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 0d98b74..f2fe447 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -276,7 +276,7 @@
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 65c955a..e9f22af 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -654,7 +654,7 @@
/* 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);