pls work

app.py

@@ -154,10 +154,7 @@ def load_db(file, k):
 
     return qa
 
-chat_history = []  # initialize chat history
-
-def greet(messages):
-    global chat_history
+def greet(messages, chat_history):
     user_message = messages[-1]['content']
     a = load_db("temp.pdf", 3)  # assuming you've uploaded the file and saved it as "temp.pdf"
     r = a.invoke({"question": user_message, "chat_history": chat_history})