如何用Python中的-0400时区字符串解析日期？

I have a date string of the form '2009/05/13 19:19:30 -0400'. It seems that previous versions of Python may have supported a %z format tag in strptime for the trailing timezone specification, but 2.6.x seems to have removed that.I have a date string of the form '2009/05/13 19