How do you pull WEEKLY historical data from yahoo finance?

import datetime   
import pandas.io.data

sp  =  pd.io.data.get_data_yahoo('^IXIC',start = datetime.datetime(1972, 1, 3),
                       end = datetime.datetime(2010, 1, 3))

I have used the above example, but that just pulls DAILY data into a dataframe when I would like to pull weekly. It doesn't seem like get_data_yahoo has a parameter where you can select perhaps from daily, weekly or monthly like the options made available on yahoo itself. Any other packages or ideas that you know of that might be able to facilitate this?