Update app.py

app.py

@@ -281,10 +281,6 @@ async def extract_text_from_mixed_pdf(file_path):
 
 @cl.on_chat_start
 async def on_chat_start():
-    
-    # Clear previous session data
-    cl.user_session.delete("chain")
-    
     files = None  # Initialize variable to store uploaded files
 
     # Wait for the user to upload a file
@@ -348,7 +344,6 @@ async def on_chat_start():
 
 @cl.on_message
 async def main(message: cl.Message):
-        
     # Retrieve the chain from user session
     chain = cl.user_session.get("chain")
     # Callbacks happen asynchronously/parallel