Update index.py

index.py

@@ -229,7 +229,7 @@ def update_output(selected_topic, selected_domain, start_date, end_date):
     
         return line_fig_1, bar_fig_1, line_fig_2, line_fig_3, line_fig_4
     else:
-        return {‘data’: []},{‘data’: []} ,{‘data’: []} ,{‘data’: []} , {‘data’: []} 
+        return {'data': []},{'data': []} ,{'data': []} ,{'data': []} , {'data': []} 
     
     # return line_fig_1