Docs say default start for DataReader should be 2010-1-1, but it returns 1 year ago from today. I prefer the docs. Thoughts? ``` >>> from pandas.io.data import _sanitize_dates >>> _sanitize_dates(None, None) (datetime.datetime(2011, 10, 3, 17, 32, 52, 969119), datetime.datetime(2012, 10, 2, 17, 32, 52, 969163)) ```