Error while downloading from yahoo finance and how to use proxy?

I am getting this error while downloading from yahoo finance

WebCorpus(YahooFinanceSource("IBM"))
Unknown IO errorfailed to load external entity "http://feeds.finance.yahoo.com/rss/2.0/headline?s=IBM&region=US&lang=en-US"
Error: 1: Unknown IO error2: failed to load external entity "http://feeds.finance.yahoo.com/rss/2.0/headline?s=IBM&region=US&lang=en-US"

What is the best way of using proxy with this package?