_save_articles doesn't test if saving article succeed, and thus can't deal cases where article is in the article.xml but something goes wrong when actual download is attempt. need to catch the error, then write exceptions so they can be tried next time
_save_articlesdoesn't test if saving article succeed, and thus can't deal cases where article is in the article.xml but something goes wrong when actual download is attempt. need to catch the error, then write exceptions so they can be tried next time