Update app.py

app.py

@@ -107,7 +107,7 @@ def load_data(selected_month):
     plot_temperature_curves.param.value
 )
 def update_iv_plot(inverter_ids, plot_power_curves, plot_temperature_curves):
-    if not loaded_timeseries_data or not loaded_other_features_data:
+    if loaded_timeseries_data is None or loaded_other_features_data is None:
         return pn.pane.Markdown("No data loaded.")
     
     if not inverter_ids: