Use cStringIO where available.
diff --git a/Lib/urlparse.py b/Lib/urlparse.py
index 37dd362..9c76272 100644
--- a/Lib/urlparse.py
+++ b/Lib/urlparse.py
@@ -243,8 +243,11 @@
         else:
             fp = open(fn)
     else:
-        import StringIO
-        fp = StringIO.StringIO(test_input)
+        try:
+            from cStringIO import StringIO
+        except ImportError:
+            from StringIO import StringIO
+        fp = StringIO(test_input)
     while 1:
         line = fp.readline()
         if not line: break