Unicode input is also accepted for stdin.

subprocess2.py

 # coding=utf8
 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """Collection of subprocess wrapper functions.
 
 In theory you shouldn't need anything else in subprocess, or this module failed.
 """
 
 from __future__ import with_statement
@@ skipping 189 matching lines @@
   - The process will be killed after |timeout| seconds and returncode set to
     TIMED_OUT.
   - Automatically passes stdin content as input so do not specify stdin=PIPE.
   """
   stdin = kwargs.pop('stdin', None)
   if stdin is not None:
     if stdin is VOID:
       kwargs['stdin'] = open(os.devnull, 'r')
       stdin = None
     else:
-      assert isinstance(stdin, str)
+      assert isinstance(stdin, basestring)
       # When stdin is passed as an argument, use it as the actual input data and
       # set the Popen() parameter accordingly.
       kwargs['stdin'] = PIPE
 
   if not timeout:
     # Normal workflow.
     proc = Popen(args, **kwargs)
     if stdin is not None:
       return proc.communicate(stdin), proc.returncode
     else:
@@ skipping 75 matching lines @@
   - Works even prior to python 2.7.
   - Blocks stdin by default since no output will be visible.
   """
   if kwargs.get('stdin') is None:
     kwargs['stdin'] = VOID
   if kwargs.get('stdout') is None:
     kwargs['stdout'] = PIPE
   if kwargs.get('stderr') is None:
     kwargs['stderr'] = STDOUT
   return check_call(args, **kwargs)[0]