User cStringIO instead of StringIO.
diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index 24b0aea..9794fc3 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -73,7 +73,7 @@
 import getopt
 import traceback
 import random
-import StringIO
+import cStringIO
 import warnings
 from sets import Set
 
@@ -379,7 +379,7 @@
     if verbose:
         cfp = None
     else:
-        cfp = StringIO.StringIO()
+        cfp = cStringIO.StringIO()
     try:
         save_stdout = sys.stdout
         try: