Add another example (saving sys.stout).

Eradicate tabs.

pep-0340.txt

@@ -579,6 +579,22 @@ Examples
                    self.lock.release()
                raise type, value, traceback
 
+    7. Redirect stdout temporarily:
+
+        def saving_stdout(new_stdout):
+            save_stdout = sys.stdout
+            try:
+                sys.stdout = new_stdout
+                yield
+            finally:
+                sys.stdout = save_stdout
+
+       Used as follows:
+
+        block opening(filename, "w") as f:
+            block saving_stdout(f):
+                print "Hello world"
+
 Acknowledgements
 
     In no useful order: Alex Martelli, Barry Warsaw, Bob Ippolito,