Fix docstring

app.py

@@ -22,7 +22,7 @@ def my_cutom_tool(arg1:str, arg2:int)-> str: #it's import to specify the return
 def fetch_binance_price(symbol: str = "BTCUSDT") -> str:
     """Get price for a token from binance exchange
     Args:
-        symbol (str): Trading pair symbol (e.g. 'BTCUSDT')
+        symbol: Trading pair symbol (e.g. 'BTCUSDT')
     """
 
     symbol = symbol.upper() #just in case