style: fix flake8 linting errors

Author: GiTaDi-CrEaTe

src/quantrl_lab/data/crypto.py

@@ -1,27 +1,26 @@
 import yfinance as yf
 import pandas as pd
-from typing import Optional
 
 def fetch_crypto_data(
-    symbol: str = "BTC-USD", 
-    period: str = "2y", 
+    symbol: str = "BTC-USD",
+    period: str = "2y",
     interval: str = "1d"
 ) -> pd.DataFrame:
     """
-    Fetches historical crypto data from Yahoo Finance and formats it 
+    Fetches historical crypto data from Yahoo Finance and formats it
     specifically for the QuantRL-Lab environment.
-    
+
     Args:
         symbol: The cryptocurrency ticker (e.g., 'BTC-USD', 'ETH-USD').
         period: Data period to download (e.g., '1mo', '1y', 'max').
         interval: Data interval (e.g., '1d', '1h', '15m').
-        
+
     Returns:
         pd.DataFrame: OHLCV dataframe formatted with float32 for RL agents.
     """
     ticker = yf.Ticker(symbol)
     df = ticker.history(period=period, interval=interval)
-    
+
     if df.empty:
         raise ValueError(f"No data found for symbol {symbol}. Check if the ticker is correct.")
 
@@ -37,4 +36,4 @@ def fetch_crypto_data(
         df.index = df.index.tz_localize(None)
 
     # Cast to float32 for Neural Network memory efficiency
-    return df.astype("float32")
+    return df.astype("float32")