diff -r 68a946e83188 -r 3f45488d70df contrib/hgclient.py
--- a/contrib/hgclient.py	Wed Apr 06 20:31:31 2016 +0000
+++ b/contrib/hgclient.py	Wed Apr 06 20:34:34 2016 +0000
@@ -1,7 +1,6 @@
 # A minimal client for Mercurial's command server
 
 from __future__ import absolute_import, print_function
-import cStringIO
 import os
 import signal
 import socket
@@ -10,6 +9,13 @@
 import sys
 import time
 
+try:
+    import cStringIO as io
+    stringio = io.StringIO
+except ImportError:
+    import io
+    stringio = io.StringIO
+
 def connectpipe(path=None):
     cmdline = ['hg', 'serve', '--cmdserver', 'pipe']
     if path:
@@ -83,7 +89,7 @@
     writeblock(server, '\0'.join(args))
 
     if not input:
-        input = cStringIO.StringIO()
+        input = stringio()
 
     while True:
         ch, data = readchannel(server)