I want to pass /dev/null as stdin and stderr.

This works from python 2.4 .. 3.2a3

It fails in final 3.2 with 'Bad file descriptor':

Traceback (most recent call last):
  File "test.py", line 11, in <module>
    Popen(['cat', 'file.txt'], stdout = PIPE, stdin = _in, stderr = _err)
  File "/opt/apps/python320/lib/python3.2/subprocess.py", line 736, in __init__
    restore_signals, start_new_session)
  File "/opt/apps/python320/lib/python3.2/subprocess.py", line 1330, in _execute_child
    raise child_exception_type(errno_num, err_msg)
OSError: [Errno 9] Bad file descriptor