added none chk

app.py

@@ -24,8 +24,10 @@ def respond(message, history):
     ):
         
         token = message.choices[0].delta.content
-        response += token
-        yield response
+
+        if token is not None:
+            response += token
+            yield response
 
 # defining chatbot
 chatbot = gr.ChatInterface(respond, title = "", description = "")