remove double commas also here

app.py

@@ -35,7 +35,7 @@ def filter_languages(search_text, selected_languages):
 def add_language(selected_language, selected_languages):
     if not selected_language:
         return selected_languages
-    selected_list = selected_languages.split(",") if selected_languages else []
+    selected_list = selected_languages.replace(",,", ",").split(",") if selected_languages else []
     if selected_language not in selected_list:
         selected_list.append(selected_language)
     return "" if len(selected_list) == 0 else ",".join(selected_list)+","