Clear inputs on model change

app.py

@@ -48,10 +48,11 @@ def model_gen(content, chat_history, model_type: str):
     return gen(content, chat_history)
 
 def model_regen(content, chat_history, model_type: str):
-    if content is None:
+    if chat_history is None:
         return '', []
-    if len(content) == 0:
+    if len(chat_history) == 0:
         return '', []
+    
     gen = MODEL_LIB[model_type]
 
     msg = chat_history[-1][0]