UndeclaredNamespace error with feedparser

What steps will reproduce the problem?
1. I am running feed = feedparser.parse(in_feed)' where 
in_feed=feeds.mashable.com/Mashable


What is the expected output? What do you see instead?
It should not return an error as all other rss feeds from the opml file are 
working.

What version of the product are you using? On what operating system?
os: 14.04 LTS
Python: Python 2.7.6
Feedparser 5.1.3
Beautiful Soup 4.2.1
lxml 3.3.3

Please provide any additional information below:

Hello I am getting the following error when using Feedparser:

    raise UndeclaredNamespace, "'%s' is not associated with a namespace" % givenprefix feedparser.UndeclaredNamespace: 'media' is not associated with a namespace

I have managed to narrow it down to one feed which is the cause:

    http://feeds.mashable.com/Mashable

I am writing a web scraper which uses Feedparser and Beautiful soup to scrape 
news articles from various rss feed that I am interested in, I am writing this 
using Python.

The error message is this:

feed = feedparser.parse(in_feed)
File "/usr/lib/python2.7/dist-packages/feedparser.py", line 4014, in parse
saxparser.parse(source)
File "/usr/lib/python2.7/dist-packages/drv_libxml2.py", line 208, in parse
eltName,eltQName,attributesNSImpl) 
File "/usr/lib/python2.7/dist-packages/feedparser.py", line 1809, in 
startElementNS
raise UndeclaredNamespace, "'%s' is not associated with a namespace" % 
givenprefix
feedparser.UndeclaredNamespace: 'media' is not associated with a namespace 

Original issue reported on code.google.com by omran.na...@googlemail.com on 3 Aug 2014 at 12:11

Reproduce the failure with http://feeds.mashable.com/Mashable using feedparser.parse, then inspect feedparser.py and drv_libxml2.py around startElementNS and the reported UndeclaredNamespace path. Done means this feed parses without raising the 'media' namespace error while the existing RSS feeds continue to work.