Update app.py

app.py

@@ -38,18 +38,35 @@ def fetch_series(ticker: str, years: int) -> pd.Series:
     )
     if data is None or data.empty:
         raise gr.Error(f"No price data found for '{ticker}'.")
-    # Prefer 'Close' after auto_adjust; fall back to 'Adj Close' if needed
-    col = "Close" if "Close" in data.columns else "Adj Close"
-    y = data[col].rename(ticker)
+
+    # Choose a price column
+    col = "Close" if "Close" in data.columns else ("Adj Close" if "Adj Close" in data.columns else None)
+    if col is None:
+        raise gr.Error(f"Unexpected columns from yfinance: {list(data.columns)}")
+
+    # yfinance can sometimes return a MultiIndex (e.g., if a list of tickers slips through)
+    if isinstance(data.columns, pd.MultiIndex):
+        if ticker in data[col].columns:
+            s = data[col][ticker]
+        else:
+            # fall back to the first column
+            s = data[col].iloc[:, 0]
+    else:
+        s = data[col]
+
+    y = s.copy()
+    y.name = ticker
     y.index = pd.DatetimeIndex(y.index).tz_localize(None)
 
     # Business-day index, forward-fill market holidays
     bidx = pd.bdate_range(y.index.min(), y.index.max())
     y = y.reindex(bidx).ffill()
+
     if y.isna().all():
         raise gr.Error(f"Only missing values for '{ticker}'.")
     return y
 
+
 def forecast_ticker(ticker: str,
                     horizon: int,
                     lookback_years: int,