How to determine if multiprocessing.Queue instance is closed

[GoogleCodeExporter]

First, many thanks to all involved for back porting multiprocessing to
Python 2.5!

Second, in my application I need to determine if a Queue instance
is closed. I am currently using ._closed attribute for that.
Since the _closed attribute is not public then this usage is not
a good practice. So, I wonder if a method, say is_alive, could be 
introduced to determine if a Queue is instance is closed or not.

Original issue reported on code.google.com by pearu.peterson on 24 Sep 2009 at 8:01