Update app.py

app.py

@@ -34,7 +34,7 @@ def today_tool(text: str) -> str:
        This function always returns today's date."""
     return str(date.today())
 
-def yfinance_download_tool(tickers: List[str], start: date, end: date) -> pd.DataFrame:
+def yf_download_tool(tickers: List[str], start: date, end: date) -> pd.DataFrame:
     """Returns historical stock data for given tickers from a start date to an end date 
        using the yfinance library download function. 
        Use this function for any questions related to getting historical stock data.