Update app.py

app.py

@@ -20,7 +20,7 @@ if uploaded_file is not None:
      seasonality = calc_seasonality(freq)
                         
      st.write(f'Seasonality: {seasonality}')              
-     if series is not None:
+     if series is not None and freq is not None and horizons is not None and seasonality is not None:
           series_train = pd.DataFrame(
                                         {
                                          'ds': pd.date_range(start=date, periods=dataframe.shape[0], freq=freq),