Handling empty DataFrames or DataFrames with no columns

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: ranaroussi

quantstats/stats.py

@@ -2146,7 +2146,10 @@ def _get_baseline_value(prices):
 
     # Handle both Series and DataFrame cases
     if isinstance(prices, _pd.DataFrame):
-        # If prices is a DataFrame, get the first value of the first column
+        # If prices is a DataFrame, ensure it has at least one column
+        if prices.shape[1] == 0:
+            return 1.0  # Default baseline for empty DataFrame with no columns
+        # Get the first value of the first column
         first_price = prices.iat[0, 0]
     else:
         # If prices is a Series, get the first value directly