Matplotlib.finance and yahoo data

Hello, quick question about the quotes_historical_yahoo function in matplotlib.finance. Typically, you need to define a start and end date for a given ticker to pull the data. Is there a way to pull ALL of the historical data without knowing when the stock or ETF started trading? I’m new to matplotlib and this list (and python, in general), so apologies if this has been asked before. If there is a searchable archive of messages, I’d appreciate a pointer URL.

Many thanks!

dk